Yes. The EU has no army, no legal sovereignty within each country, etc. It's an alliance of countries NOT a single federal government. The individual countries remain in charge of themselves and the alliance is supposed to be structured in a way that only paases things the countries actually want.
trumpdong then makes a comment that I interpret as saying the EU doesn't have a lot of power over member states, and saying that the worst which could happen to one of them is to be kicked out of the EU.
Slightly shocked by the idea that the EU should be doing something worse than expelling a member for not following the Union's rules, I use a _reductio ad absurdum_ and ask if they thought the EU should be harder and actually perform an armed invasion of a member state that didn't follow them.
They complained kicking out the worst. I suggested one possible worse possibility (again, in a reductio ad absurdum rhetoric), trying to understand what they thought should be done more than "just kicking them out". They agreed with it.