Please define "bad behaviour". You see, just because you think something is bad behaviour doesn't mean that everyone else has to agree. Whether a person's behaviour is good, bad or normal very much depends on the lens through which you view that behaviour.
Maybe. BUTT
1. In the meantime we have had SOME way to codify good or bad, via the philosophy of ethics. Granted, it's not perfect, eg, if you go full utilitarian, if you could torture a kid for all eternity to make everyone, all 8 billion people, happy, it would be a GOOD thing, but it's a start and such extreme edge-case examples don't happen in real life. So, yeah, we'll burn that bridge when/if we ever actually cross it. But I haven't seen any attempt to see that argued in ANY philosophy of ethics, anyway.
2. Nor in any traditional idea of ethics, either, or not in a coherent and consistent, much less valid way.
Like, seriously, going by the idea that a new minority is automatically right and worthy of support, then you could use the exact same argument to offering all your empathy to the minority of slave owners in Haiti, and not to the majority slaves. (For our butthurt fanboy whargl friends, no, that's not putting words in your mouth or anything, it's a valid
reductio ad absurdum
)
3. I'd still be ok with the activists actually showing any empathy to either side, regardless of whether it's group A or group B, and regardless of what their definition of good is. But I haven't seen them giving a flying f-bomb about either the group A they're supposed to be supporting, or group B they're abusing. They only seem to care about scoring thumbs up and retweets from other activists, at the expense of BOTH groups. Which, say what you will about the fallibility of ethics philosophy, it's failing HARD to qualify as good in ANY.