Some people believe that removing someone from life support is wrong and is "playing God" because it could most likely cause death. With that line of thinking, shouldn't life support be considered "playing God" since they are sustaining life (especially when there is almost no chance for recovery)?

I think you're right to wonder about the 'playing God' objection. First off, it's not always clear what the objection actually is. Sometimes, it seems to be the straightforward claim that only God may make decisions about life and death (and so about when to prolong life or hasten death); humans may not. But, if this is the claim, you're right to notice that, if it works against a decision to hasten death, it should also work against a decision to prolong (or sustain) life; and so, the objection ends up also undermining the position of the person making the objection. But I wonder if the objection is not sometimes a different sort of claim, one that doesn't suffer this sort of problem. The claim might be that only God may decide the time of a person's death, particularly when means are available to us humans to prolong or sustain that life. In other words, the claim might be that, so long as there are means available to prolong a person's life, we humans must decide to use those means to prolong that life...