I empathize a lot with this comment.
In tech (though I would guess as in many other technical domains), many people do seem to easily bully people for not knowing things or making mistakes. I'm guessing it's just people having high insecurities themselves, it's even more of an ego thing when considering that computer things are considered as a "nerd" pastime (a group considering itself "smart"). Not knowing things - even things that we would have thought are really simple - should be OK on an help channel as long as you're not abusing the helpers' patience.
I've been a witness of these situation countless times, the sane way of handling this for me have been to just consider that these are mostly people externalizing their poor self esteem and to just continue conversation (at worst with the other people) as normal.
I don't get it, why would you even be mad about someone referring it as GNU/Linux?
In that case it's even just either X org or the wayland compositor that may implement that, not "linux".