Absorb is super easy to counter.
As a Dark sided player.. just drain the person. It still is effective in draining their force pool (doesn't give you hp though). Once they're out of force pool and are forced to turn off absorb, hell you can be lame and drain spam them so that they can't get anymore force power back. Or you can be a nice guy and let the fight go on, even sided.
If you're light sided... you don't really need to worry about it. Only offensive powers light sided people have that absorb counters is pull and push. But the effectiveness of those two now aren't to knock someone down, just to get em closer, stop em, or push em back. Even with absorb on, it still moves them slightly in that general direction. And if they're jumping over a pit, push them even with absorb on, they stop dead center and fall.
Hell, even with practice you can always pull+kick someone with absorb on.
Absorb isn't the all powerful uber move. Only reason you have to complain about it is if you're a grip or lightning whore. In which case you have nothing to be bitching about, cuz you suck, heh.