I am not a BJJ student, but based on my experience in Capoeira, another martial art associated with Brazil, the machismo of the originating culture can't be discounted. Brazilian culture carries an emphasis on male virility which can translate out to an atmosphere which at least implies a "dog eat dog" setting where strength is rewarded and the kid gloves are off with an undertone that breaking the rules, or showing disrespect, will lead to you getting punished if only with something like a slap on the wrist. In practice, it's not usually that bad, with the strength being more show and implication than actual attacks, but I've seen enough people who made the mistake of making a mestre, particularly one from Brazil, look foolish by catching them with a sweep, and the roda becoming much more serious and you not being allowed to leave until you've been put in your place.
Not mentioned in the question, but I think germane to the question, is that this can also result in prejudice against women, non-binary folk, and non-heterosexuals (Capoeira is in a weird space in that we revere characters like Madame Satã, but with an undertone that he was so manly in his crossdressing that it doesn't count), and when things get really bad, there is the issue of sexual abuse, which the Capoeira world has been reeling from lately due to recent revelations about CDO leadership. Again, I'm not a BJJ person, so I don't know how prominent this is there, but for Capoeira, the machismo culture results in casual sexual aggression, especially from people of higher rank (and I'm pretty sure that Capoeira has some additional issues due to the "hidden/criminal" history of the style where no one wants to be a snitch, and politics can kill your progress dead if you cross the wrong people), and I've known a few women in BJJ who've commented on getting more than a few "friendly" squeezes during grapples and, again anecdotally, being openly gay can result in a surprisingly large number of heterosexual men engaging in groping as a show of dominance.