A: There’s no reason the person inflicting I’m Lost! on someone else should be immune from being chosen by that person to “help them find their way.” Such an immunity would break the card in two-player games, and we wouldn’t want that.

…So I’m Lost! is not intrinsically good or bad for the person playing it, nor for the person targeted. Fluxx is sort of mooshy that way sometimes. Having to assess that kind of situation is what keeps the game interesting!

Given that the person who is Lost gets to choose who will help them, and that person must pick one of their Keepers to give to the Lost player, it’s easy to see how the Lost player could use the situation to their advantage. For example, if they choose someone who only has one Keeper in play, their “guide” doesn’t even really have a choice which Keeper they give up, so, in that case, the Lost person essentially gets to choose what Keeper they’ll receive.

Note that, as written, it’s entirely possible to play I’m Lost! on oneself! This was not an accident.