Effective Altruism, as a philosophy, is very simple. Basically, the argument is that if you shouldn't do bad in the world, that means you should do good. If it is morally wrong, objectively, to kick a baby or not save a drowning child, then it is morally right to treat others with kindness and spend some of your time and energy helping others. If it is true, morally, that you shouldn't cheat or steal, it is true that you should give and sacrifice.
This is a very controversial take. I understand it particularly well, in my opinion, because I grew up Catholic. Catholics, in my estimate, spend a lot of time avoiding the negative. Whipping themselves into a frenzy over impure thoughts, past mistakes, and current temptations. As a Catholic teenager, I was constantly guilt ridden. I was very concerned with what was going on in my own head, trying so hard to avoid slipping up or thinking the wrong thing. Policing my own brain rigorously, stressing about intrusive thoughts to an almost psychotic point. Little did I know, no one cared about what was going on inside my head. Not God, not others, not anyone.
If I had spent half of that time focused on doing good, I wonder where I would be? Sure, I spent a lot of time volunteering and being nice to people, but I now wonder if I did that because I felt compelled to, or if I do it in order to "avoid" being a bad person. I have a theory that the way the religions have been traditionally practiced is counter to this Effective Altruism idea of "doing good," and rather focus almost exclusively on "not doing bad." Doing good for others, in most religions, is placed lower in the hierarchy than worship and avoiding sin. The ideal Christian, or Muslim, or Buddhist, is one without temptations, who has control over this thoughts and actions, and could sit in deep prayer for hours, talking directly to God. Sure, there are some rare examples that differ from this, as the Mother Theresa's of the world have shown. These people, in my estimate, are the true heroes. Sure, you can live your life as another Desert Father who sits in a room and meditates all day. Sure, you can be totally without temptation, without impure thoughts, and never lie, cheat, or steal. But if you don't do anything for other people, if you don't contribute positively thought the world, if all you do is sit in a room full of silence and purity, what was the point of having you here?