I’m not sure you understand what a doomer is. Doomers (as a meme) are people who are incredibly cynical and jaded; who believe that we as a species are fucked, and any attempt to stop it is like an antelope thrashing in the mouth of a lion. This idea isn’t inherently right-wing or left-wing, nor is it specific to any particular country (though it’s probably more common in the left-wing western anglo-sphere). It’s the idea that while it technically might not be too late to reverse course and solve things like wealth inequality, climate change, police brutality, fascism, etc; the fact that the people who benefit from these things are also the ones in power means it’ll never happen. It’ll always be 90% words, 10% action until it truly is too late; at which point they’ll declare that they tried as hard as they could and there’s nothing else to be done.
The people you’re describing aren’t actually doomers, they’re just concern trolls.