Okay, I'm not a believer in the fabled Batman/Robin subtext. I've never seen the subtext, it just seems to me like Wertham was overreacting to seeing the strongest relationship in Batman's life with a male character and people have picked up on this since.
I'm actually pretty difficult to argue this point with.
I can see where you're coming from if you're going to argue specific interactions between Dick and Bruce that seemed slashy, you can argue if they are fatherly affection vs romantic affection. That's cool. I'll usually fall on the side of fatherly affection, unless the scene is written by Devin Grayson. But she's only one writer in sixty years worth of writers on page and screen, and she's the exception when it comes to this. Other writers tend to be very careful about how they portray the Batman-Robin relationship.
I can see where you're coming from when arguing how either character interacts with women vs how he interacts with men to argue that they are homosexual, but honestly I'd need a long road paved specifically with Dick Grayson interaction to convince me of that particular pairing. (I also find that arguments about Bruce's interaction with women indicating anything other than a repressed heterosexuality, sexuality which has been pushed aside for his War on Crime, are barking up the wrong tree -- but if you think you have a good one, you're welcome to try.)
Those, and others, are still reasonable points.
However, there is a sexist argument that I've seen drummed up in these discussions, and if I see someone use it, I'm calling them on it.
It's the "What kind of a 35 year old single millionaire would adopt a teenaged boy?" argument.
This assumes that men of a certain age are natural sexual predators, unable to interact with any children other than their own without being watched. It's a prevalent idea in our society, one that keeps men out of professions like teaching and childcare. It comes to a basic devaluation of fatherhood in early years, one that discourages men to be actively involved in parenting. It plays on the idea that dealing with children is for women, and any man who would dedicate any time with a child that he doesn't have to has something wrong with him.
Basically, it leads back to confining gender roles. It tries to shame men away from nuturing duties (because they are "woman's work" and no "real man" would do "woman's work"), and it contributes to a lot of the bad stereotypes associated with homosexual men in our society.
It is cultural, yes, but it is also wrong. It's wrong in real life, and it's simply incorrect in Batman continuity (because we know why Bruce tries to help angry young men, he sees himself in them).
It's a really sexist attitude. Now, yes, it's probably what's been printed in the Gotham gossip columns, and whispered around WayneTech Water Coolers. But come on, we've all read and watched Batman. We know Bruce Wayne far better than the extras who gossip about Bruce Wayne.
So, find something more specific, Batslashfans, because that stupid generalization just won't wash.
Oh, and if someone tells you that one of your arguments is based on a sexist stereotype, and you go "Oh, no! I don't think that about Shazam or Green Arrow" but keep coming back to the generalized argument to support your point, you're still using a sexist argument because you haven't called to mind anything specific about Batman over, say, Green Arrow or a professional wrestler, just a generalization about 35 year old men.