Ah yes, how do I grab a swarm?
Why does a hovering flying creature have to 'stand up' when its knocked prone?
How come a construct can be put to sleep?
Why can I still shift while blinded, I don't even know which direction to protect?
I'm of the mindset that the word used as part of a condition has absolutely nothing to do with what your character is actually doing to the monster. Conditions are merely terms created to give the player a general visualization and justification for detriments they create.
They could have simply replaced Grab, Blind, and Stunned with Condition Red, White and Blue. If your power stated that your attack deals 1d10 damage and inflicts condition Red until end of next turn where Red was detailed as the same game mechanics described under 'grab'...you'd be less likely to question the logic of this power on any given foe and would simply accept the mechanics.
Calling something Condition Red, isn't exactly conducive to a smooth running game as you'd have to endlessly check the rules on what that means. By simply giving it a name like Grab, many people will grasp the general game mechanics without requiring a rules reference or memorization.
To summarize, your characters actions are in some way causing any given creature to act differently. How you are doing this is completely open to your interpretation and requires no justification.