Yeah, the pistols do normally fire that slowly. Primary fire is more for specific situations where you just need to fire a single precise shot.
There's also a little trick I discovered. If you click primary fire then quickly click and hold secondary fire, you can get the pistols to shoot rapidly one after another. Play around with different timing and you'll see what I mean.
Honestly, though, you're probably best off using the pulse rifle. The pistols are powerful, but they're a little too hard to use effectively.
That said, it can be really fun to try and clear a level with just pistols, and no saves :)
swimthefish: I also seem to remember that from time to time the pulse rifle would jam, and that it was by design, rather than a bug. Adds to the panic and tension I guess.
hippox99: So the human race can make space ships, but they forgot how to make proper guns? Of course gameplay doesn't have to be realistic, but this is obviously a bug or an engine oddity.
What you're showing in the video is an engine oddity, but the pulse rifle does deliberately jam from time to time.