[quote=@Archmage MC]
Double, they didn't clone buu, they just tried to make one of their own and failed horribly. And they know about Buu because Freeza knows about him. He mentions him directly in Resurrection F as well as Beerus, who Freeza has met.
[/quote]

That all happened several years in the future. As in, after Frieza died. But even for the sake of argument, there's still no means or motivation whatsoever for Frieza wanting to do this. At all.