He stated so himself in a documentary of Trek that aired on PBS.

In response to your claim, here's a link to an interview he did in 1997 where he was asked if he was a fan of Star Trek:
As you can see, Ira Behr does not hate Star Trek, he was a fan of TOS, and I assume you will not make that claim again in the future without a proper reference.Greg_Magnus asks: Were a fan of Star Trek when you were growing up?
Ira Behr: Yes. I don't think I missed an episode of the original series. Though, like most fans, I was disappointed with season three. I think the show that really won me over was "Charlie X". When I lived in Malibu, Robert Walker, Jr. ran a store there. I used to see him on occasion. I used to think: "Oh my God, it's Charlie X." But I never watch the show in repeats. And except for going to the movies when they were released, I didn't think much about Star Trek in the intervening years.
Because I've read a lot about the guy and he never gave the impression that he hated Star Trek. He said that he hated the Roddenberry Box and he left TNG after one season out of frustration, but the Roddenberry Box was one of Gene's later ideas that wasn't present in TOS or movies II-VI. Ron Moore also had trouble writing within the Roddenberry Box, but he was one of the biggest Star Trek fans to ever write for the franchise.How can you claim it's an exaggeration if you didn't hear him say it yourself?