*LONG POST WARNING*
Josh has two sons, the youngest of whom is biracial.
A lot of these fitness personalities have two accounts: One for business/fitness, and one for family and friends where they share more day-to-day stuff. Reason being, since a lot of people (such as myself) actually follow them for real fitness tips and not to simply lust over them, people don't want to see content that's not related to fitness or a healthy lifestyle. Josh is sexy as hell, no doubt, and a lot of guys want to emulate his workouts to obtain (their version of) his body. It amazes me how so many guys lust after guys who are fit without doing any work to improve their own bodies.
On the business/fitness accounts, they'll typically only follow like-purposed accounts, so if that's predominantly or primarily other guys, that doesn't mean anything at all. Just wishful thinking and fantasizing by lustful gays.
Since these guys know that many gay men follow them, it's actually a good business strategy to keep wheeling them in with bait by not showing much of anything about their private lives to keep that fantasy alive. Another IG fitness personality I used to follow was Josh Swan, who I also thought was sexy as hell and offered great fitness content. But then he got engaged, then married, then had a baby in rapid succession and most of his content switched from fitness to his family. As a result, I unfollowed because he stopped posting what I initially followed him for, and I imagine a lot of gay guys did too once they saw behind the scenes into his personal life.