Uhm... I hope this is a joke, right?
So, let's say I build a house for you and you pay me full price for it. Now you move into that house and you realize that I made lots of mistakes which make living in this house rather uncomfortable - with your argument in mind you would not be allowed to complain about these issues, just get some stuff from the market and fix it yourself, right?
Seriously, people payed money for this expansion and there are some serious bugs that need to be fixed in order to fully enjoy the WHOLE game again, some things like the overall performance became very bad after this update and the performance of the AI became so bad that it took almost all the challange from the game in terms of singleplayer gameplay (for example, I wasn't able to win games in admiral yet, though after this update I steamrolled the whole galaxy on grand admiral difficulty with advanced starting AIs - this should not be a thing).
Criticizing these problems with the game and "demanding" the developers to fix them is not "stupid" or anything - it's totally acceptable. We should NOT rely of "third party modifications" to the game to make it playable again. However, this does not mean people should use insults or anything like that - this is unacceptable and should not happen, this is not constructive feedback.
Fixing bugs like the current ones is the developers job and they are probably working on it right now, after all, this was a really huge update and now it needs lots of time for the bug-fixes, having mods as temporal fixes is Ok but we should NOT RELY on these to make the game bug free - this is just encouraging Devs to not properly program their games.
EDIT: Wasn't there even some kind of controversy with the Devs of Bethesda where they said something similar like "Let the modders fix the bugs", this really hurt their reputation with their new game Fallout 76 in mind, it's full of bugs, actually there are so many that even modders would have incredible problems to fix everything.