Insurrection was fine. I also remember good reviews, stressing the aspect that it was brighter than First Contact. Nobody cried doom when it came out. It wasn't as good as First Contact, but it was solid and good fun. The bashing started when Nemesis sucked as well. And now, 15 years later, everyone is like "Oh I hated it from the start" when most of them thought it was okay back then
the box office performance was way down from FC, it made $20 million less. It had a solid opening weekend, then fell flat after that, disappearing from theaters in about a month.(which was fast for those days) This indicates that it WASN'T particularly well-received, and its reputation is not solely a "Nemesis thing."
I'm not sure how many here are fans of internet review site "SF Debris," but he covers exactly this topic in his review of this movie.
He speculates that it's a "fridge logic" kind of movie, where the more you think about the movie and its premise, the more it falls apart. The more you think about the humor, the lamer it seems.
the real issue with INS is that its premise is just irretrievably flawed. It's a movie with the "heroes" on the wrong side, and if you can even ignore that, it's boring and the humor is lame.