Just saying, if you’ve read/watched Harry Potter thoroughly you should know this (Not saying that you lack knowledge btw). Here’s why if you didn’t know.
Harry was part of a prophecy. Well, Voldemort made him out to be. The prophecy said that a boy born at the end of July with parents who had thrice thwarted him would defeat him. It could’ve been Harry or Neville, however, Voldemort thought it more likely that it would be Harry.
That’s basically the reason summed up. It’s sort of hard to explain completely.