> Why would Google want to invest resources on giving Microsoft an unfair advantage over themselves?
Because it's good for the users.
It's not good for users to allow Microsoft to get away with vendor lock-in. This may force Microsoft's hand. That's good for users.
Why would Google want to invest resources on giving Microsoft an unfair advantage over themselves? Microsoft being jerks is the rule since that open letter Bill Gates sent to the Homebrew Computer Club.
In other words, why would you invite a guest that is known to steal stuff and not flush toilets into your home?