Refusing to play with short stacked players?

[Taso]

Err, didn't think I could give the subject justice in the subject line. Here's the situation.

We've been playing about 2 and a half hours, we're down to 4 players in the game, it's a cash game, .25/.50 I've been doing well the entire game and I'm up about 185BB. The only other player with any real $$ infront of him announces cash out, he has about 120bb infront of him ($60) the other two players have around $6 and $30. I tell them I'd be willing to keep playing if they added on to their stacks. The way I see it, I have very little to gain, and a lot to lose by playing with people who have no money in front of them.

I never (ever, ever, never have, not even once) cashed out of the game, and I vowed to do it after a few hit and runs from some regulars, but the ones who I wanted revenge on weren't playing anyways. In a casino, I don't care about a hit and run. At a home game, when the players are limited, I can't stand it.

Anyways, the question is, is me not wanting to play with 2 very short stacked players bad etiquette? Also, is my reasoning ridiculous? (having everything to lose and nothing to gain)