I do not know about your sources but rimming is not exactly homosexual exclusive behavior. Heterosexual couples also engage in rimming. In addition rimming is not all that far removed from a certain common form of oral sex called cunnilingus, perhaps you have heard of it?
I have no idea if Blake is gay, straight or bisexual. I am not concerned about it. He seems to be a nice guy and he is performing on a sex site for which work I assume he is being well compensated. I enjoy his work and I think he is cute. In fact at the risk of sounding really crude, he could sit on my face any time he wanted a contribution to his retirement fund.
Last night I was speaking with a friend of mine who does photography and videography for a company here in SF. I mentioned the dialogue here about whether the straight boys are really straight. My buddy commented on his experience which is not all that different from mine. Sexual behavior is very much a continuum not a fixed point. A lot of the models he works with [as well as some clients I have had] identified as straight but made money by having sex with men. But the key is when they get paid, where do they go and who do they spend time with? Do they go home to the wife or girlfriend? Or to a sugar daddy? Or to the boyfriend?
One of my more energetic clients is a very personable white boy of 23 years of age raised in Hawaii. He is tall and very cute. He could suck a beach ball through a garden hose and do so better than anyone I have ever met. But he is married with a child. I once asked him why he chose to make his money through sex work with men. He told me that he could make 400 to 500 a day and support his wife and kid. He had no other marketable skills and was a "lousy thief". His wife was cool with him having sex with men but not with having sex with other women. His attitude was as long as he could make money in the sex trade he was going to do it. Meanwhile he was supporting his wife and kid and attending the local community college where he was getting a certificate in aircraft mechanics.
There are many young men on the margins of society who make money by doing photos, videos and sex work. They do so for a variety of reasons. But I would not make assumptions about their sexual orientation based upon what they do on the screen.