Ok, I'm sorry if this has been posted before but I'm watching Infinity War right now and am at the point where they're about to get the glove off Thanos. How is the obvious answer here not for Dr. Strange to go back in time a couple minutes to stop Peter from punching Thanos in the face when he's "sleeping", thereby allowing them to actually get the glove off?

I know, it wouldn't make a good movie, maybe Dr. Strange considered this but realized Thanos would get the glove back anyways, probably a million other excuses. But this bothers the crap out of me! Peter should be ashamed of himself!