I honestly don’t know much about how light speed transportation works in the Star Wars universe. I do know that the movie very carefully framed the light speed collision as a move of last resort, done out of desperation, (and that it only worked because of certain circumstances like the First Order ships not realizing what was being done until it was too late to act). Based on that, I’m willing to believe there are legitimate reasons why it’s not used as a normal weapon in the rest of the franchise—reasons that, in this particular case, were overshadowed by the desperation of the situation. That’s how the event was framed.
And if we look through the Star Wars universe and find that there really isn’t any reason for this technology to not be used this way… isn’t that more of a plot hole in the Star Wars universe as a whole, rather than in this latest movie? To have had a technology as powerful as light speed be presented as ubiquitous as it is, and then not use it to its full potential? (I mean, collisions have clearly always been possible in the universe. Isn’t it in the very first movie that Han explains to Luke the necessity of calculating a precise path, lest they crash into a tiny piece of debris that destroys the ship? Yet the previous movies never had to explain why this technology wasn’t already weaponized.)
Perhaps that’s where the upset at this scene is coming from—that a previously unrealized plot hole has been realized (not introduced). (But again, that wasn’t something the movie itself was saying, given the way it framed the scene).
I really liked The Last Jedi. I thought it was remarkably respectful and aware of the movies that came before it while also (quite explicitly) taking the story forward—something which is necessary for the franchise to last.