how dumb do you have to be to say "europeans"

As an European I think you can. If you refer to the cultural aspect, Europe has several cultures but we all share some similarities as we mixed together for centuries. From a geographical point of view, we are used to live on a limited amount of space compared to US or Russia or Australia for instance, and distances are short between each city. Our cars look the same all over Europe for this reason. We do bike a lot too.
Also we have political level and the EU and so we share common laws and debate all together in the same parliament. So yes, you can say Europeans and it's fine even more since Brexit.

I work on Ethereum and 🦊 but I'm here for memes

It's hard to get without context tbh, or is your port an answer to something? Maybe I haven't followed the same topics as you or algorithm is not providing the same to both of us.

I wasn't discounting the word entirely - I was referring to the kind culture pigenholing some people do in the context of US vs EU