you said “most people realize” it made it seem like it’s “common sense” to not give an exact answer.
it is. it’s common sense in the way that you could more accurately call it social protocol. it’s a little like passing people. In the states you pass people on the right just like driving on the right side of the street. There’s no reason you couldn’t pass* people on the left but social protocol dictates that given the two choices and all else being equal passing on the right is the default. Personally I don’t find exact time’s weird. oh sure I may sometimes use relatives terms “Half past 3” “Quarter till noon” but I would never find anything out of the ordinary with someone giving me the exact time. quite the contrary I would be grateful. When I say quarter past. I literally mean it’s 1:15 or I would use more deliberate times.
You’re asking why people are weirded out? because you’re speaking in a manner which is atypical. It’s not wrong, it’s not rude. to be honest it’s probably not even all that uncommon but it’s atypical. If someone tells you it’s “Oh eight hundred hours” you assume they’re militarily related because it’s atypical and it might even weird you out.
I’m more interested in how you know people are weirded out. Time is such a minor thing that unless you’re reporting it in a 24 mode quite frankly I fail to see why anyone would even mention it. By the time I’ve opened my mouth to say something the moment of awkwardness has long gone. it’s only weird for maybe 7–10 milliseconds. If noone has actually called you weird for your time relational speech then maybe you’re making a bigger deal over this than you should be.. kinda like me and this ‘far too long’ post.
*passing in this case meaning I’m coming one way and you’re coming the other.