He must not be aware of how much his bitterness towards Stallman shines through, because he doesn't bother to either justify it or apologize for it. The natural arc of the essay, starting with his "feeling of impending doom" and proceeding to the innocuous reality, seemed headed toward an ending that addressed or explained his initial negative expectations. Instead, he takes mean-spirited and irrelevant potshots at Stallman's social skills. Bizarre.
That's a rather loaded read. I read it as a guy going to give a presentation and finding out that he was going to be protested against. He was nervous about a confrontation, but the GNU folks were polite, attentive, and didn't disrupt his talk.
If someone wanted to portray that sequence of events in a hostile way, the usual course would be to not admit any trepidation and mention dismissively that some fanatics held up signs.
He might be bitter on the subject elsewhere, but casting that blog post as such seems to be reaching.
It's not my read that's loaded, it's Pike's language. He's relentlessly negative about Stallman. Whether his dislike of Stallman is justified is another question, but that's my point: he doesn't bother justifying it. His only concrete criticism of Stallman is his claim that AT&T never threatened to sue anyone over the patent. His writing manages to drip with disdain without making any other concrete claim:
"hippie pipe dream"
"promiscuous computing"
"harangue"
"I always thought only boring people went to Heaven."
"characteristic inaccuracies" (here referring to the idea that AT&T ever threatened to sue)
"bizarre form of political correctness"
"eager misguided nerds who in a healthier environment would probably be protesting the killing of rats in biology class"
If he had come right out and said Stallman was an attention-whoring fool whose ideas were incoherent religious baloney, we'd expect him to back it up. So why should we accept him using indirect language to say the same thing? I realize he was posting something he wrote fifteen years earlier, but he didn't say anything to disown or apologize for his intemperate language.