Some people don't have a sense of humor, think that about say's it all really.
And some people just don't like seeing men kissing...
If people want to believe it was a harmless "joke", that's all well and good and up to them. Personally I see it as an intentional use of delicate subject matter to cause a fuss (no advertising is bad advertising and all that...), which - to me at least - is far more offensive and insulting than seeing two men kiss.