In Germany the liberal institutions decide who can and cannot run, and they have decided the commies are out

Back in 1946, it was decided that antidemocratic parties shouldn't be part of a democracy. Hence antidemocratic parties are illegal.

That's it. You are very much allowed to abolish private property if you wish to do so. You'll just have to do it in a democratic manner.

And it just so happens that abolishing private property is very much not a popular idea.

(No, the current German government can not decide who can run in elections.)