Perhaps he's currently kidding himself, or us – or both. Perhaps, for the sake of argument, despite what he actually says Daley 'really' is gay, or bisexual. Unintentionally, it reinforces straight-and-narrow and increasingly obsolete ideas about what boys should and shouldn't be – if they don't conform to that, then they 'must' be gay. In a sense it's the 'friendly fire' version of the homophobic tweets Daley has experienced, and the bullying that made him change schools.
But unlike Daley, I'm not quite so inclined to laugh it off. This kind of gay insistence about Daley's sexuality (and other pretty boys in the public eye, such as the Olympic gymnast and Strictly star Louis Smith) isn't malicious, in fact it's meant affectionately. But whatever the reason, I suspect many of them might be rather less convinced – or interested in expressing an opinion at all – if Tom didn't look hot in a pair of highly abbreviated swimming trunks.