It's kind of an internal meme: he says "we have to be thoughtful about this" or "we have to approach this thoughtfully." Almost every tough question from inside Google is met with an answer that contains the word "thoughtful."

It seems to mean "there is no easy win for me in this situation, so I am passing the buck to (presumably) a committee of other people who will think about it instead, or perhaps a power-hungry VP who has a vested interest in making it happen."