2 wrongs don't make a right. And again, there was a non-hypothetical, objective argument that could have been made to defend Minsky. RMS did not make that argument, instead he went off on some hypothetical that may or may not have happened, but there is at least one eyewitness testimony that says it didn't.
And this wasn't RMS's first time wading into bad positions on topics that honestly aren't up for debate.