I kinda get why people in the fandom tend to have strong negative feelings about the Quenya ban because forbidding languages is not typically a good look, but for what it's worth, as a member of a nation that has had to deal with cultural genocide time and time again, I don't think it's really the same thing as the typical language policies of colonial empires.
I don't know how to explain this exactly, but... there is no other attempt at suppressing culture, the Noldor did do them wrong and Thingol is within his rights to feel betrayed... Yes, it was a badly thought out act of wrath, but it's not really comparable to the actions of real-life governments, and as someone whose nationality by necessity makes one conscious of the existence of such, it kind of puts me off when that is invoked. And I'm not saying that you cannot feel otherwise about it, because it is a thorny subject. But it's just not how I understand it.