Knew you were talking about Kurtzgesagt. I'm kind of a sucker for their videos. While they are obviously liberal, they are self-aware and meticulous enough that it's mostly fine, imo.
While it's obviously correct that self-help and the enormous industry behind it mainly exists to cope with (and profit from) the enormous human misery that capitalism causes, as well as a way for firms to maintain the productivity of their increasingly overworked and stressed workers, it's not something to be ignored. Just because we believe we have a clearer insight into the system around us does not make us somehow immune to its effects (on the contrary, perhaps). We are just as vulnerable to stress, alienation, loneliness, and depression as everyone else, and if we cannot find ways to cope with that we will become increasingly incapable of acting for social change. "Self-help" is no replacement for solidarity and genuine connections, but, in the absence of that, if writing a few lines in a notebook every day can give me the energy to get up in the morning, to join a party, to attend meetings, to do activist work, then why the fuck not?