I'm conflicted, but I'm not sure why

I saw this today over at Waving or Drowning?.

My first reaction was laughter. It's obviously satirical, playing up one of the essential flaws in the anti-gay marriage argument.

My second reaction was unease, but I'm having a hard time translating this niggly feeling of discomfort into words...

UPDATE: I removed the graphic, because it was saved on my work computer and since I only have one more week of work, it would disappear anyway. You'll have to head to Mike's site to see it.

Also, I think I've figured out why I felt uncomfortable with the site. It makes fun of the protestors, which I do find funny, but it also makes light of a serious issue. However, sometimes I need to lighten up and not take things so seriously.