So you need to be an experienced dev to speak up against a toxic work environment? I do also cringe when I see comments like yours attacking the guy for doing something you wouldn't do. He probably mentioned the amount of lines of codes as a way of saying he did put a lot of effort(is common knowledge that on itself is a shitty metric). Maybe he, also wouldn't want to be hired by someone like you either, not would I.
I'm not saying he shouldn't speak up against a toxic work environment. I'm saying he's doing it on LinkedIn in a way that makes him look bad and could hurt his future career prospects.