No, that's the exact opposite, because there was no reason to think that Dumbledore was gay prior to that announcement. Goldstein is a very-obviously-Jewish name, and anyone who read it would assume he was Jewish.
If if were utterly pedantic (which I am), I'd point out that:
1) There is the word "to" added in the middle of the 'incantation.'
2) There is surely not enough hate in him at the time to use the killing curse to it's intended affect.
3) I am relatively sure that just saying some words that kind of sounds like a spell while your wand is loosely between the index and pointer fingers -without any intent to form a spell or an affect- would not cause one of the unforgivables to come out at full strength.
4) Even if the 3rd point is true, who the f*** is stupid enough to hold their wand like that? You don't need magic shooting out to be a problem, it could drop and break, thus causing an actual issue.
Ah, excessive and unneccessary nitpicking, it's almost as fun as answering rhetorical questions.
Also, to respond to point09micron_process 's post, if you look in the 4th panel the picture is still up in the gameboy screen. It could have frozen on that, but I don't believe it has.