Question about clients?

I am very grateful for the work that you guys put into developing these clients for us moochers. I have a quick question about the modselector/no debuffs.

Why are we able to select to not be affected by stun, blind, confuse, paralyze, etc, but not with slow and quiet? Is it just a lot more difficult to dig into the code and figure that out? Or does it make it too apparent that you're using a client?

Forgive my ignorance, I have no idea how exactly it all works, and I was just curious.

That wouldn't be a matter of coding.. and I'm not sure that would be possible, but don't quote me guys.