It's much more critical on condensers just because they are so much more sensitive. Dynamics are inherently more immune to pops and sibilance, and they usually have some kind of integrated pop filter built in to them. People often use dynamic mics because they can be hand-held, which many singers are more comfortable with. Obviously, a pop filter is impractical if the singer is dancing around.
But that doesn't mean a pop filter wouldn't be beneficial if it's on a stand, especially for a singer that works the mic as if he were inflating a balloon.