It's not fast though. The gameplay progression is SLOW. How else do you define a fast paced game? The classes limit you in nearly every aspect, so unless you're claiming it is "fast paced" compared to, say, Counter Strike (which almost all games are), how are you determining that it is fast paced at all?
Combat style and movement speed, that's what determines the speed feel of a game, and thus far, you are the only person i have ever met that feels TF2 plays at a slow pace.
We can agree that UT and Quake playes even faster, sure, but not that TF2 is a slow paced game, you move fast enough for most classes, the combat is generally very straight forward, arcady if you will, and quite spammy, there's allways lots of things happening on screen (unless you camp, but people can do that in UT aswell), and you can allways get to some combat very quickly if you want to.
The game moves plenty fast if you want it to, keeping in mind that it is a CTF gametype and not a DM free for all, which isen't so supricing, it did start its life as a Quake CTF mod, Team Fortress goes back a long ways, it's older than UT, probably even older than Unreal.
To me, "fast paced shooters" is a sub-genre of shooters that Quake and UT fall into. TF2 isn't something I would put into that genre. To me, it's like comparing a Honda Civic hatchback to a Corvette. No matter what you do, you can't make them equals.
No, that genre is called "Arena shooters", not "fast paced shooters", that's not a genre, but a label you put on games that has speed and twitchy gameplay, all shooters of all genres can be fast or slow, it's not a genre thing, it's a speed thing.
Even CS can be considdered a fast paced shooter in it's genre, it certainly moves 50x faster than Red Orchestra does, and they are both MP "tactical shooters".
I'm not quite sure what genre we should say TF2 belongs to though, it's not really an Arena shooter, nor is it a Tactical shooter, it falls somewhat awkwardly between the two, the best i can describe it with is "Arcady MP CTF game", and as such i'd have to compare it to the CTF modes of other games, and as such, it moves plenty fast, not UT fast but fast.