Google Releasing AdMob SDK for WP8

I read that Google was going to release tools for their own advertising division for WP8. I'm careful what I read on WPCentral, but if this is true, it kind of irks me. I mean didn't Google say that users are not on windows powered devices so it was no use to them to have their apps on the platform?

But now, all of sudden they want to make money off the platform which "has no users" with their advertising platform. Why can't they make their apps for WP if they're willing to do this?

I hope wp devs boycott AdMob