I don't think being "mopey" about the historical context you live in is necessarily self-defeating or nihilistic. Accepting things are shitty and feeling hopeless is what can motivate people to act against it together. In a time of hyper-capitalism, alienation, and commodification of all forms of "happiness," being unhappy and embracing it can be an act of protest. When other people see you're unhappy with the current state of things it can help them be comfortable with expressing the same feeling. The idea that expressing unhappiness is a bad thing prevents it from being a force to bring people together. Instead people feel like they should always be happy and hopeful and motivated, and that only losers are unhappy, but everyone is unhappy to varying degrees and not accepting it fully causes a lot of issues for people.

I think if anything we live in a time where we're struggling to find balance between these anxieties and hope for any potential change for good, but I think the two are more connected than most realize.