Brother & sister don't carry the same sexist connotation as wise and beautiful woman or prick, but you already knew that.
If not, you'd be fine with Hillary sisters provided that Bernie pricks becomes a thing, right?
See, there you go trying to change the argument again. You're pretty good at trying to manipulate, but it's sadly obvious. For the record, in the context of "Bernie Bro's, the word "brother" has no place in the discussion at all.
"bros" and "brother" are not the same thing. Attempting to argue they are just so you can invent some comparison to "sister" is a little ridiculous. I said "bros" and you countered with "sister".
I get it, you're probably an old dude so this is hard for you to grasp, but "bros" isn't synonymous with "brother". That appears to be the root of your current confusion - hopefully I cleared it up for you so you can stop trying to make correlations where one doesn't exist.
