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 
There's certainly an attitude of "we should be able to federate with large leftist communities and then spout false right-wing talking points without being challenged >:("
The overton window is a big part of it. They're totally immersed in a world where they're as far left or almost as far left as it's acceptable to go. There's a completely distorted view of politics where most of the electorate in the US genuinely thinks the Democrats are at least somewhere past the center left.