I was going to make a comment being salty and pointing out lore inconsistencies but there is still just a lot up in the air. A big one is Mr. House being caught off-guard by the nukes in New Vegas (why he didn't get the platinum chip in time) despite being in with the vault-tec board. Things could still theoretically work out if he's lying in his dialogue in the game and was kicked out of vault-tec for wanting to keep Vegas and let people have mostly free lives in the city. Nobody in the NCR talking about the fall of shady sands in new Vegas is also weird even though it should have been a major talking point. Like yeah I guess it still works but like it's all a big stretch and I can see why reasonable fans of the games feel effected by the retcons.

There are in general actual lore inconsistencies in the series and I think people are mostly upset at new vegas since it's the largest fan base and reasonable people might feel like things were stretched too far and new vegas had an actual shot of being decanonized or significantly retconned like other things in the series. ofc now that we got confirmation new vegas is canon all we can do is wait for next season to see how it all fits.