The contents of a persons heart are known only to them and fundamentally unknowable by anyone else barring some scientific breakthrough, so they cannot and should not be subject to sanction. The words that come out of their mouth, on the other hand, are discernable.
You say the correct way to read your comment is as a criticism of the rhetorical support for violence in the parent, but the parent comment in question treats of violent opposition to Nazism, an inherently violent ideology, which you seem to be overlooking.
Allow me to illustrate how this looks from where I'm sitting:
Abel: Nazism is good! I support putting [people I dislike] into camps and killing them.
Baker: I find Abel's views repugnant and threatening to me, and if he expresses them in my presence I will punch him.
Charlie: Baker is terribly violent!