And we shouldn't allow this concept to go unchallenged here on Lemmy.
Commenting on an active post is not brigading
Posting a link to something is not brigading
Commenting on something you were linked to is not brigading
The only thing that might be brigading, but isn't because it isn't a real thing, is someone explicitly going, "Hey everyone, go here and harass this person"
It's all fine and good that we have some new rules to keep the peace with other instances but we must fight against 
Another part that adds to this notion is that libs generally only encounter crudeness from literal children or right wingers.
They think the real world politics is some West Wing-ian paradise of polite discussions and good faith arguments. Only MAGAs resort to ad hominem, ofc, Donald Trump is bad partly because of bad policies but mainly because he's crude! Good Republicans are polite and also want what's good for the country, they just disagree on methods!
This probably stems from anti-civil rights movements saying the blacks are impolite or crude when demanding basic human decency.
Also historically untrue, on at least one occasion, Abe Lincoln bullied an opponent to tears with ad hominem attacks.
Either way, they fully buy into the scam that politeness and taking the high road will win the day except the part where liberalism has been in decay for decades due to what basically amounts to stomping your feet at conservatives every time they slide into fascism.
And they keep doing it, Sisyphus with the rock, Charlie Brown with the ball, libs with politeness. Guess what? Not disrupting evil in any meaningful way means they get to continue to make things worse and get away with it.
Likely, and even before that. Using clothes, language, hairstyles, accent, pronunciation to separate the "good" people from teh "bad" people goes back to forever. That's a big part of how Hexbear even happened; Verbal vulgarity and insults and cruelty that was appropriate to the lies, deception, and normalization of horror coming from the Democrats. "We're going to talk to you with the level of consideration and politeness you deserve, which is none you fucking monsters".
This might sound a little
but in highschool my history class had a facebook group for discussing the politics that came up from the readings and discussions for us to turn into essay bits and junk. We had a conservative weenie in there and while I was very far from being a raging communist or even a socialist the both of us got into it about healthcare laws and other bullshit which eventually just turned into me berating him for just straight up lying about the laws and policies, the fact that he read the entire obamacare law (LOL). Everyone fucking hated all of his shit I got so much praise from everyone in that group, including my future girlfriend. The only time debate was ever tangibly good for me.
That brings back memories of how one of my poli-sci classes back in college usually ended up with me shouting down some reactionary while the professor just did nothing. And I was just a tepid sucdem who read Matt Taibi's tripe back then too lmao.