SWORDS don't swing 10 times per loving second.
Fine, have an excessively slow sword which would take forever to swing and kill a person. Enough time for them to kill you.
1. SWORDS don't take 1000 hits to kill.
You'd be pretty annoyed if you got in a sword fight, on an online Lego Game and were killed the moment a sword hit you. Of course it's not going to be realistic in that sense, and the reasonably high-speed, which isn't that fast, as mentioned before, makes up for this. The damage gives overs and yourself a chance and makes it fun, while the sword speed means you won't spend forever attacking someone with "low" damage.
2. SWORDS aren't 10 inches long.
We're LEGO sized people. We're not going to be able to carry a foot-long sword. Overly large swords just get in the way and are exceedingly ugly, IMO. The Size is just right for a sword, on a Lego Person. Too big and they get in the way when equipped, or look silly, or they don't look right when placed on bricks.
3. SWORDS are wielded with two hands
We're LEGO people, essentially. Considering technically, it's not possible for a Lego person to have two hands reach the same close spots. Plus, two hands aren't that attractive, IMO.
Special feature : DAGGERS aren't crappy 1-inch long crappy toothpicks.
All the above things. Plus, describing something with the same word twice in a sentence just sounds stupid.
If you have a problem with all the swords and daggers, make one yourself. No one is forcing you to download the Sword packs.