i have a passing interest but i haven't really gotten into it yet because of depression and life stuff. it's definitely something I would encourage as a leftist if you have the capacity. if you're lucky and there's a left wing fighting gym in your area that's the best bet, at the "regular" ones you're fairly likely to run into right wing nutjobs/bigots unfortunately. wrt which one to choose, BJJ seems very practical and unlikely to give you a head injury just from sparring etc. if you do something like boxing you will sustain head injuries from sparring which is a concern. there is no avoiding it in a striking sport. obviously being able to throw a punch is still very appealing but i would personally stick to the heavy bag in that department to save what's left of my brain cells.