Our parliament wanted an evening curfew at 20:00, the opposition wanted it at 22:00 because there was no evidence/data supporting why it should be 20:00, They settled at an evening curfew at 21:00 and still no-one can give us the proper data or scientific prove at which time it becomes effective.

These career politicians are negotiating my freedom like it's worth nothing anymore.
This is some proper fucking banter, I live in a city with 1 million people and 300 cases. We had pubs open with >1.000 cases for months. There's no rational person that understands the measures here any more.
The NY Times just did a decent piece on this yesterday:
https://www.nytimes.com/2021/01/23/health/coronavirus-curfews.html
The challenge is that not everything lends itself to data. For us to do a randomized control trial between communities that we *presume* are similar, with one having no curfew and the other not, would raise all sorts of issues of ethics, enforceability, dependent variables, undue influence, etc. In fact, if someone even attempted to do a scientific study like that, my immediate "intuitive" reaction (paraphrasing a biostatistician cited in the article) would be to distrust the experiment design and methodology. There are so many holes where you could be lead astray.
The next thing then to ask is, "Well, if we cannot easily or reliably test it with useful data, should we not even bother trying?" That's a whole other question though. Sure, some level of skepticism is healthy. But on the surface, any measure that socially interferes with the r0 should make the models go down in infections. Yes, there will be compensating behaviors -- like people clandestinely gathering for beers in homes because they cannot be on the streets or in markets after a certain hour. But is that enough statistical grounds to reject the hypothesis that curfews might help overall? Not really.
So yeah... it's good to have science to back things up. But not everything in a complex society can be enforced and measured accurately to know with a strong level of statistical significance. Unless you're China and you can pretty much lock the population in doggy cages for weeks at a time.
IMO, politicians can't be the only voices in the decision. Health experts, virologists, economists, mental health experts, child development experts, etc. all have something semi-valuable to add to the conversation. But there isn't going to be one solution that satisfies everyone. Which is where it becomes more important to follow a shared set of rules than it does to patchwork reject this or that item on some grounds like a Chinese take-out menu.