Even if we are generous and accept that GU was more criticized than other bullshit papers, the claim still needs to prove that the difference of treatment is due to some real bias and not a simple fluctuation.
"I saw 2 persons being judged by a judge, and turned out they were both guilty of the same crime, but the first one got less than the second one. The first one had the same letter in second position in their family name as the judge, so it's the proof that judges are biased favorably towards people who have the same second letter"
But then, the problem is that "their own bullshit papers" is doing a very heavy lifting here. The point of Hossenfelder is that String Theory is as bad as GU. But is it really the case? Hossenfelder keep saying it's true, but a lot of people are not convinced by her arguments and provide convincing reasons for not being convinced. The same kinds of reasons don't apply to GU, so it already shows that GU and String Theory are not on the same level. Even if String Theory has some flow or is misguided on some aspect, does it mean that the level of rejection in an unbiased world will obviously be the same as any other bullshit theory.
Another aspect that is unfair is that a lot of "bullshit theory within the sector" dies without any publicity. They stop rapidly because from within the sector, it is more difficult to surface them without being criticized early. For example, you can have 100 bullshit theories "within the sector" and 3 survive and surface without being as criticized as GU while 97 have been criticized "as much" as GU during their beginning which stopped them growing. Then, you can just point at one of the 3 and say "look, there is one bullshit theory there, it's the proof that scientists never confront bullshit theories when it comes from within". Without being able to quantify properly how the GU-like theories are treated when they are "within", it is just impossible to conclude "when it is from within, it is less criticized".