I think you are taking this way too seriously. Does Frank Millers All Star enforce an image of Batman are a fucking nutbar who abuses kids? No, because it's dumb as all hell and everyone knows it. Not necessarily. When I was just getting into comics I picked up an issue of ASBAR. It did not turn me off comics, but I did believe it was in canon, so yeah. It's really easy for new readers to pick up ideas from just comic they've read, if that's their only experience with a character.
I happened to get into comics through the DCU, so I knew Batman wasn't always like he was in ASBAR. And most new readers today would probably be familiar with Nolan!verse Batman, so they would also have a good example to fall back on.
But, like I said, it's the principle of the thing. I find this so out of character for Batman and it really bothers me. Yeah, I know he used guns a couple of times during the golden age, but I think most people would be willing to admit that golden age Batman had a few issues.
The thing that bothers me the most is that guns are an acceptable aspect of the golden age Batman mythology. DC apparently has no problem with a Batman who murders people, even though that bears little resemblance to his modern character. But I sincerely doubt that DC would ever bring back the homoerotic aspects of Batman's relationship with Robin, as, you know, that would bad. But somehow guns aren't. (I know someone is going to say that the two aspects are vastly different and, while they are, they are also both illegal, immoral acts.)
And, yes, I am taking this way too seriously, I know. But it really matters to me.