Guess I missed it. I don't remember the NFL saying anything one or another. And, quite honestly, shame on the NFL for politicizing its brand. Employees want to get political on their own time, that's fine, but when an employee hitches his employer's identity to his cause, that's a problem.
My personal feelings have nothing to do with it. BLM is based on a myth and apocrypha. The facts run counter to the narrative that IS based on feelings and perception. It's got more in common with religion than social policy and is an insult to true civil rights struggles.
Kapernick's a twit, and so is anyone who buys the hype.