Look, this isn't that difficult. It's not an admission of guilt that Tom Brady destroyed his cell phone rather than hand it over to the NFL. Not of deflating his balls, which is the sort of thing that really should be kept between consenting adults in the bedroom, and not of anything else either. It's just common sense. Here's why.
The NFL, speaking of the organization as a whole, is utterly incompetent at stopping leaks. Indeed, one half-suspects that they use leaks as as a back-channel for disbursing information that they want exposed to the public but are unable to release publicly. Even if you accept that they wouldn't deliberately leak the contents of his cell phone to embarrass him out of spite at his complete and utter inability to care about the very serious issue of ball size, which is very charitable of you given the NFL's track record as a bunch of spiteful idiots who blame others for their faults, you're still handing a celebrity's cell phone over to a group of people who probably have TMZ on speed dial. Even if there is nothing incriminating on a legal or cultural level, there's a wealth of personal information on there that Tom Brady probably didn't want getting out to the general public because it's personal.
And yes, the NFL did say that they would allow him to turn over only the texts he felt was relevant to the investigation. That position would have lasted as long as it took for them to not find anything incriminating in the texts he turned over, at which point Roger Goodell would have taken another hit off of the Bong of Self-Righteousness, insisted that the lack of evidence was not evidence of lack and it was a shame that Tom wasn't fully cooperating given how far they'd bent over backwards to meet him halfway, and demanded the cell phone anyway. Because it's the NFL and that's what they do.
So Tom destroyed his cell phone. Good for him. This doesn't mean I have a deep-seated sympathy for the injustice he's enduring or anything--Tom Brady has enough money that sitting out for four games is pretty meaningless at this point. And he probably did the thing he's being accused of doing, and it is against the rules of the game and as such is at least nominally within the purview of the NFL to enact disciplinary penalties over. And he's a total stranger living in another state and I have no real need to feel deep emotions on his behalf. But I would have done the exact same thing in that situation.