The issue is when people take it to the extreme (like someone who literally argued that a person doing mere charity or volunteer work is bad, because they are wasting time and effort that they could've spent making money and recruiting to contribute more charity and volunteering), or just sidestepping "altruism" entirely and using the name and community as a stepping stone to push your unrelated scam.
I don't know whether or not SBF genuinely believed in effective altruism, but if he did, he let the "principles" override common sense.