Is it true that Netflix simply throws customers out and can never watch Netflix or something again?

If you e.g. 2 years customer or so

Yes, for users who either have not used their account in two years or whose account has never been used a year after a new registration.

https://www.derstandard.de/story/2000117630716/netflix-wirft-inaktive-kunden-raus

No, that's not true unless you haven't been to netflix for several years. Such stories can be heard everywhere on the Internet. You don't have to worry about that

For years, I have often used netflix e.g. My father my brother etc and me too

Then that doesn't apply to you.

Yes, if you have been inactive for years and do not respond to feedback. This is very nice from Netflix.

This is actually nice from Netflix. Netflix writes to them and first asks if they have not used Netflix for two years if they really want to keep Netflix.
Why pay for something you don't use?
If they didn't have to and could actually continue to collect the money. If someone doesn't quit, it's not Netflix's job.
So is very kind of Netflix.

Just like that, however, no one will be kicked out as long as you adhere to the terms and conditions.