In most situations, the dudebros are the ones to respect the medium in question enough to fight to gatekeep it from being ruined. Early Internet had a solid split of "nerds" and "bullies" before the normies got their grubby hands on it.
I notice this as well. Halo would be a great example of this.
I don't think you really see "dudebros" in particular infiltrate fanbases, rather normies tend to be the ones that infiltrate instead.
In most situations, the dudebros are the ones to respect the medium in question enough to fight to gatekeep it from being ruined. Early Internet had a solid split of "nerds" and "bullies" before the normies got their grubby hands on it.