Am I the only one who sees the major flaw in this movie?

I'm looking at the messages on this board and I'm surprised that no one has complained about or even mentioned the major flaw in this movie, and here it is: Why does everyone in that town just automatically believe that some random stranger is a man that they supposedly knew for years? I mean let's say that Luke did look similar to Peter Appleton, and even if Luke had been gone for almost 10 years, you'd think that the people in that town (especially Luke's own father) would've still been able to recognize the physical and personality differences between these two people. That's where this movie loses me. You need a LOT of suspension of disbelief to be able to watch this movie.

And there could've been a sensible explanation as to why all the town's people thought Appleton was Luke. For example, hypothetically Peter and Luke could've been twin brothers who were separated at birth, and Luke grew up with adoptive parents who never knew that Luke was a twin. That would've sensibly explained why they all really thought Peter was Luke. If only whoever wrote this movie had thought of that, then this movie could've been much more believable. It's a shame that this movie is so flawed because it had the potential to be great.