Yeah it's horrifying. We are fighting against massive societal currents for even the smallest amount of progress, and the fact that most people don't even see the issue makes it that much worse.
Kind of like being a communist.
Personally, I just limit my exposure to shit that triggers that response in me. We might not be able to save the Omelas kid, but we can walk away and try to convince others of what is happening. Pace yourself and pick your battles. Activist videos like Dominions and Earthlings are tools we use against carnism - you don't need to expose yourself to that stuff if you're already against it.
I hear going to animal sanctuaries can be real good vegan self-care.