"Players" very much including DMs here, I presume?
Most of the absolute worst takes on alignment that I've ever come across "in the field" have been from DMs. Indeed the very first time alignment became an issue in D&D for my group was one I've mentioned a few times - when a DM told us we "had to" kill a bunch of literal toddler-age/development orc babies or we couldn't be considered "Good" (really channelling Gygax there I guess, but we didn't know that), we were just 12-13 y/o kids but this was beyond abhorrent to us.
Over the years I've seen DMs behave unreasonably re: alignment way more than players. Sure there's Lawful Stupid and CN causing big problems from time to time, but for every Lawful Stupid Paladin or Cleric causing the entire session to grind to a halt, there are two DMs trying to litigate the exact and precise bounds of certain alignments, particularly CG and LG in my experience (as someone who has almost never played a PC who wasn't NG, I generally avoided these conflicts), usually totally and completely unnecessarily and dragging the entire session down as a result. Stuff like "Well you can't go along with this plan, you're LG!!!" and the plan really isn't that illegal (or simply pits one law against another) and would do huge good, or "Omg how dare you steal that item from these obviously-bad people, you're CG, and it's not Good to steal!" (insane take imho but I've seen it). Not that that never happens when alignment isn't involved, but it drags out far more when it is.
And yes the "invade places, kill the "bad" people who live there, and take their stuff" deep-set colonialist-imperialist subtext to D&D is one of the things we generally don't openly talk about, but which certainly problematizes D&D on a fairly deep level. There are ways around it, and I know a lot of modern WotC and 3PP adventures skirt or avoid those tropes, but some don't and others just run smack-bang into other problematic tropes (like "black bagging people and imprisoning them forever with no trial, no real judicial or investigatory basis, and no chance of reprieve is cool, actually", I mean did the CIA write this lol? IYKYK re: which WotC adventure I'm referring to).