Well, the least to say: its a very complex matter i think. Its tough to make a generalized conclusion. You can find examples for the good and the bad.

Developed nations have different interests and motives. On one side, moral awareness to aid other and developing nations, but also parties protecting their own interests. We also see the influence of consumers in organizations like Fair trade, with different effectivity.

Regarding vital resources like fossil fuels, big money often wins but exceptions are possible. The public opinion always matters but can be a bit erratic. Still, the demand for fair clothes, chocolat and soccer shoes are notable as example.

I can go on and on about some matters, but in general you can say: the assumption in your question cannot be affirmed. Global policies are very diverse and too mixed in effects. The interest of developed nations are not free from selfish acts, but can be positive as well.

I don’t think first world countries encourage any kind of political ideology to other countries. It is simply not in their interest and even if it were, it is too much work to entice an entire country into a belief that is alien to the citizens. Most countries choose (or at least aspire) to become democratic because among all the flawed ideologies, democracy is the only one that gives people a chance to rectify their mistake, every 4 or 5 years. So yeah, people choose democracy. Its implementation can be flawed though. Some countries stay true to the fundamentals of the ideology and allow people to make their choice, while others run wires through the loopholes and make a sham of it.
That aside, first world countries trample all and sundry for their personal gain. They don’t discriminate political ideologies when it comes to furthering their own interests. You’ve given an example that I’m not familiar with but there are many, many other examples to prove this point. For example, in the middle east of the world, a developed country continues to have extremely cordial relations with a country that is autocratically ruled. In the same neighborhood, the same developed country invaded another autocratic country (quoting that they were against autocracies) and plunged that country into leaderless chaos, which continues till date.
A little further down in south Asia, the same developed country sided with a sham democracy, when it went to war against its stable democracy neighbor. It was in their interests to keep the stable one under control (chaos), as it served their purpose. This happened in the 70s. Right now, the stable democracy is still there and on the up and so, the tables have turned. The developed country now sides with their former enemy…as it serves their current purpose!
Look, every country has its own interests to take care of. No one should begrudge that. If a first world country tramples a third world country, most of the blame should go to the leaders of the third world country. The history of the world is there for everybody to see. There are only a fingerful of first world countries that don’t poke their noses into other people’s business and mind their own business. All the rest have a history of running roughshod over other countries or even destroying them. So, if a third world country to willingly offers its head for sacrifice, they should be talking the blame too.

Actually everything I’ve read points out that Africa is the country that inspired the world with their cotton blend fabrics.
I haven’t found anything regarding African cotton being sold to England or to America, as both produced their own, at least in the 1700’s, Manchester for England and the Southern states in America.
After the Civil War, India, Egypt and other countries were desperate to supply it and keep that profit for their own country so they got in the business.

If anyone does answer your question, as to England/America refusing to buy African cotton, I’d be interested in the answer.

Developed countries encourage democracy in other countries because it is to our advantage. We support dictators when it is to our advantage as well. We often encourage democracy when there is a dictator in place that is not to our advantage (such as a communist dictator). In Latin America especially if a democratically elected dictator was not going to prove to be an ally, we would support an effort to depose them, then usher in a new sympathetic leader, no matter how brutal they are. Unfortunately I don’t know enough about the rest of your question to answer it, and I’m not trying to be extremely cynical, but we don’t prop up democracies because we’re the good guys and we always stand for fair elections and against autocracy.

Wow, I had to jump in on @KNOWITALL answer with a small correction….quite big in fact. Cotton wasn’t ‘desperately’ sent to England by India. It was taken and fed into the ‘satanic mills of Victorian England’ (famous quote by an eminent person, which incidentally wasn’t challenged by any English historian, who were present in numbers when that speech was made, or after). They took ALL the cotton and when the famed handloom weavers of India cried out on the injustice, the British went in, smashed their thumbs (which is an essential tool for hand weaving btw) and destroyed the hand weaves….burnt them…so this notion of ‘desperate to supply’ was a bit of a slap on my face when I read it. To be fair, Egypt might have been desperate to supply like you say…I don’t know their history. I suspect they weren’t desperate…but could have been. I know about India though….the largest suppliers of cotton and cotton cloth in those times…even now….

@AK Interesting, thanks. We could be talking about different things, but I’m not sure. I was speaking of supplying raw cotton around 1860.
There is a lot of history behind cotton for several hundred years.

@KNOWITALL We’re talking about the same time period. I read your answer and saw the passage where you said – after the civil war. That’s exactly when Britain turned its attention on India. They lost one golden goose and wanted to absolutely make sure they didn’t lose the other. They ‘colonized’ India and ruled over it. Another example of how first world countries trample over others to further their own cause. History of cotton starts in India and stays there throughout history, my friend. This is where the first cloth was woven, worn and exported. The bit I explained about British taking cotton, is a big part of cotton’s history. The act of British destroying handloom weavers and stealing their cotton, was the starting point of civil rights movement in India….a significant phase in history…and then Gandhi came and….anyway, I can ramble on forever because I’ve studied it…I wasn’t trying to confront you or anything. Was just trying to clarify an error…so please, no hard feelings…

@AK No, no hard feelings at all, I love to be educated on thing’s like this. :)
Perhaps I need to read more on Indian history to get a better picture from that POV.