The frisson of attraction that abides in the Johnny-Bodhi standoff is erotic, all right. But it isn't homosexual desire. It's narcissism, the delight of seeing one's rare magnificence in someone else. The fact that Johnny and Bodhi operate on different sides of thelaw only highlights their mutual identification. Johnny is drawn across that line not because he wants to have sex with Bodhi, but because he wants to be Bodhi—or, more accurately, because he isBodhi. If this isn't obvious enough, Johnny's new girlfriend, Tyler(Lori Petty), who is also Bodhi's ex-girlfriend, says it repeatedly.
Now, 300 has earned more than $200 million in America alone,from an overwhelmingly male audience. What more plausibly accounts for this? That 20 million closet cases snuck off to see an illicit fantasy about bare-chested men in Hellenic Speedos, or that young men from the vast heartland of this very conservative, Christian, pro-military country flocked to see an unabashedly heroic tale of Occidental, republican military glory? To believe the latter, all you have to accept is that, in imagining the sort of heroic figures they themselves would like to be, straight men would project onto them not just excellence but physical beauty. Shouldn't a guy be able to do such a thing without being called gay?
I'm not really buying this argument. I think a male "project[ing] onto [idols] not just excellence but physical beauty" onto other males does have elements of homoeroticism. Think of the equivalent scene with a male and a female action hero. Having a male-female fighter come to respect each others' fighting skills often ends at very least a fling.
This is not to say that fetishizing action heroes is a homosexual rather than a heterosexual trait. However if most of your action heroes are male as is most of your audience, it can end up that way. Similarly, this doesn't make people who are doing this physical beauty projection gay. I'm not even sure if it would be more common among homosexual males. However, it is a same sex attraction. The narcissism aspect doesn't negate that by any means. I know I'm more attracted to females that compete with me and have skills I want to have. The problem here is that the author is treating gay and homoerotic as if they're pejorative term. Neither should be.
As a side note, I think it is important to maintain a space for friendships. Friendship doesn't have to be erotic and can be both male-female, male-male, and female-female. However, friendship isn't about physical beauty.
Finally, as a side note, I've been told I have consistently terrible taste in male action heroes. I believe this.
[Update: Some edits to fix grammar mistakes.]
[Addendum: I think a great example is once scene between two cops in Hot Fuzz. It's not really a beefcake scene, but it goes with heroic recognition/male bonding while very obviously playing with homo-eroticism. In most cases, I don't think it's intentional though.