“It’s like saying “The Gra? That person who broke all Minhagim he didn’t like while writing math books?” It’s true that he wrote a math book. It’s true that he did (or at least tried) to change a few old and respected customs (Duchening daily comes to mind).”
Again, this is just like when one of the Chabad posters brought up other Chassidishe groups with similar hanhagos. If you want to make a thread questioning why the minhag haGra people are OK with being mevatel old minhagim in several areas, you are free to do that. But, that is not this thread; this thread is about Chabad. The fact that it’s possible to have kashas on other groups doesn’t answer anyone’s questions on Chabad. It’s just a diversion.
On a side note, this was probably just an accident, but from the way you worded it, it sounded like you were saying there was a minhag to duchan daily and the Gra got rid of it. It’s the other way around; minhag Ashkenaz is to only duchan on yom tov, minhag haGra is to do so daily.
Although I think it’s just a pointless diversion to bring minhag haGra into this anyway, I do think it’s worth mentioning that it’s not all that comparable. The Gra’s changes, like not wrapping tefillin on chol hamoed, had precedents at least in the Sphardi mesora. The questionable Chabad practices being discussed had no basis in anything prior whatsoever. Chabad seems to have developed this unique view on mesoras like, “well every minhag has to have been made up by some guy at some point.” You should understand that that isn’t how anyone else views it at all.