The problem is that it's really just lazy writing. This is much like all the nerd-debate over The Matrix movies. Or Lost. Stuff like that.
Best case scenario, the writers and directors wanted things to be open, and let the audiences reach their own conclusions. Inception is a good cinematic example of that...I'm pretty sure when asked 'did the top stop spinning' or 'was Leo still dreaming,' Christopher Nolan has said something to the extent of 'I don't know. Pick whichever option you prefer.'
And that shit is a lazy cop-out.
But what's even worse is when the writer is just like 'sure, this makes enough sense...whatever...can I have money now?' I think Edge of Tomorrow is a lot closer to that. You can try and find proposed explanations that you agree with, but in the end, they are all just pure fabrications by people wanting closure.
It would be easier to overlook if the rest of this movie was simply not as good as it is. And it is, indeed, quite good. If they didn't want people to think about it, they should have gone with a simpler concept. Really, they did quite a good job of just keeping you busy and making you not question the inevitable paradoxes that plots involving time travel, alternate realities, ect create. You focus more on the characters. You get just enough repetition to get a good sense of how awful such a situation would be. You see Cage cope with humor, anger, fustration, ect. You start to realize 'awww, he's so in love with this woman, but it's an entirely one-sided relationship.' It's a little past a mindless action movie, IMO. And it's a shame that all it really needed was a tiny bit more polish on the script to make it a truly great movie.