Why do players like to repush the same lane where they already took an Inhibitor?

If you push a lane where an inhibitor has already been taken it takes less time for the super minions to get to the enemy base pulling enemies away from other objectives sooner, thus making it easier to take other objectives faster.

Maybe they need 200g for an item (Happens to me alot)

So that they can get aced inside the enemy's base, of course.

...no, seriously, I'd like to know too. After 15 minutes, lanes other than mid cease to exist in some low elo players' minds. The whole point of getting super minions is for them to distract the enemy so that you can make a play somewhere ELSE. (This includes another inhibitor -- two lanes of super minions are much better than one.)

Depends on the situation.