The UK is in Europe.
The fact that we know what they mean by saying the UK is no longer in Europe does not make that statement any more correct.
I often see comments from people outside of Europe who think that the UK "left Europe" (not realising the distinction between Europe and the EU). I don't blame them, but I think it's worth pointing out.
Respectfully, I disagree that they are not realising that. They are just using language differently, i.e. "Europe" in a political / legislative context can mean "the EU", i.e. a political / legislative boundary not a geographic one.
You can say" they're wrong" if you like, but use of language is more commonly viewed as descriptive not prescriptive: "how language is actually being written and spoken rather than trying to identify a correct way"
tl;DR People know what they're saying and you understand it, so what's the issue? what I said in the 1st comment.