When to just call ?

[JDMcNugent7]

I know and always hear that calling is the weakest play in poker and you rarely want to just call. I know in drawing situations many times it can be justified and is often even the right play when drawing. Also I know it can be good to just call when you are slowplaying and have some big aggression from opponents.
However, I was just watching some poker on TV the Full Tilt Poker thing with all pros, no ametuers, and they Just Call all the time. Much more often than I do. In many situation I would be re-raising or folding where they just call- and they arent drawing either or slowplaying, they Just Call with 2nd and 3rd pair all the time.

So is just calling really all that bad ?