The concepts involved are still evolving.
In public health, they tend to talk about MSM (Men who have sex with Men) rather than sexual identity/preference. There are literally thousands of men who have sex only with other men who do not (and would not) identify as "gay."
Over a lot of human history, it was acceptable to be the "insertive partner" but the "receptive partner" was looked down on. Also, the idea that sexual activities are related to maleness or femaleness (gender) is not always the case. Every culture has different standards for both sexual and gender roles.
I think we've got to grow beyond the idea of sexual identity. Having sex with a man is not necessarily an emotional or intellectual connection, and further, having an emotional/intellectual connection with another man does not necessarily mean having sex with each other.
If a model says they're straight, as "gay and straight" are matters of self-identity, then they're straight. Perhaps that's oversimplified, but it's the basis I work with.