That’s called privilege. You literally don’t realize what a burden it is for some people to comply with voter registration requirements, because your life is such that it’s easy for you.

The “privilege” you are talking about is the exact same privilege the parent comment assumed:

I just have to show up with my ID, doesn’t matter if it’s for the EU parliament or the local city senate.

The “privilege” you are talking about is “having an ID card”. Every time you obtain, renew, replace, update, or otherwise contact the state bureau handling ID cards (usually, the DMV), they are required, under federal law, to update your voter registration unless you specifically decline.

The European standard is “get an ID card, show up and vote”. We implemented the European standard back in 1993.