So, they succeed and repeal it a third time. What can be done to stop them from trying again and again and again until they get away with it?

Not much really, unless the EU takes a big turn to the left. Which is unfortunately not something that's likely to happen anytime soon.

The left? The authoritarian politicians pushing this legislation in the EU are more leftist than right.

They're usually liberals, so right wing but they don't specifically hate homosexuals.

> They're usually liberals

The irony.

Aside from that I also thought EU is more left than right wing right now. Nothing what they try to push this term of office seems right wing to me.

There would need to be some form of punishment towards them for their failure to deter them.

The most 'accessible' options to a disgruntled populace (or a small portion of it, down to N=1) are generally recognized as extreme things that very few sane people are on board with, because they are recognized widely as bad precedents for societies. Things like issuing death threats, assassinations, or burning down parliament buildings. To state what I hope is already obvious - this is not an endorsement of violence. For one Japan's history of 'government by assassination' was incredibly ugly and helped lead to extremism which helped lead to Imperial Japan's conduct becoming notorious as they did.

There are other far more peaceful options to be considered but they would require high degrees of coordination and agreement. For an example, the classic Amish shunning - if legislatures faced utter social ostracism for their attempts then they would be unlikely to attempt it again.

I'm not sure what policies could even provoke such extreme responses as those listed (violent or otherwise) in the first place, but for better or worse Chat Control isn't one of them. My most realistic guess would be that trying to abolish the pension/retirement system altogether.