Back in my day effective altruism was mainly about finding charities that aren't essentially scams (way harder than it looks). Scene has apparently moved on to other things since I followed it a decade or so ago.
This is a super-simplified summary, but I think it's generally accurate. The basic thesis of EA is "it is your duty to improve/save as many human lives as you can." At some point, a lot of EAs realized that there were many more future humans than present humans. Once you widen your scope in that way, you start realizing that long-term, catastrophic risks (climate change, nuclear disaster, misaligned AI) would affect…
No, it's not about having any duty. (Where did you get that from? Friendly question)
Instead: If you want to help others, then, you can to stop and think, do some research (or read others') before deciding where to spend your time and money.
Something like that.
Still, a movement formed around a concept that involves money (donations, lots of them) and status (getting appreciation for helping others), is going to attract some of the wrong people. So maybe it's unsurprising that from time to time, we're reading negative things about movements formed around EA-the-concept. Although the concept itself is neither good or bad (well except for in some people's opinions).