We already know the political slant of "experts". Making "experts" write the community notes would lead to them being as untrustworthy as "fact checkers".
No because I can leave a social network and go to some other website or publisher that allows me to publish whatever I want. The worst thing that can happen is that they delete my comments.
You can't escape the state. If they don't like what you post they'll beat you up and put you behind bars. Not good.
Regarding your "democratically appointed censor" point, freedom of speech means that I should not be a slave to whatever the status quo is.
Here in Spain we eliminated special classes for disabled children and put them in the normal classes.
The obvious result: everybody is worse off. Disabled children are not properly accommodated and the performance of the rest of children suffers because of everything going slower. And all the responsibility of dealing with the situation falls on the teachers, who aren't adequately equipped.
No need to be a nazi or anything to see why that's a bad idea. Of course, the left destroying public education is nothing new.
Anyway, back to your comment: we were talking about the perception of Germany from outside Germany.