The story is well known
The sign was there
And together with it there was an Amnesty International sticker.
So it really depends on what people want to see, more than what's really there.
I've seen much worse sign, like professors not receiving at their office even if they were required to, posting signs with the new address where you could find them (usually their private studio office)
And they only received if it was "really needed" otherwise you just sent an email and waited.
That's what made me really furious when I was a student.
Women were more concerned that they traveled 100kms from their home towns to meet the professor and talk about their thesis and finding their door shut, not of some stupid signs that was clearly a joke made by someone who wasn't a threat to anybody.
The real threat came from the polite, well dressed, highly educated, power angry monsters, those like Epstein.
Stallman is the exact opposite of that kind of men.