You have no idea. Whether it's about GDPR, the Google Books lawsuit, surveillance reform, relationships with China or whatever else the policy issue of the day might be, Kent Walker was involved. He's not a leader? He has hundreds of people under him. Your "only promoted recently" makes it sound like he's a small potato. He's been around for a long time. When Google wasn't even born, at Netscape he gave JWZ the bad news about Microsoft and bad-attitude in the antitrust lawsuit (https://www.jwz.org/gruntle/rbarip.html).

Source: I used to work at Google. I would have asked Kent a policy question well before Larry or Sergey.

Kent Walker had a leadership role back when I was hired at Google, which was nearly a decade ago. Titles don't necessarily mean all that much - he's been handling high-level legal issues (including dealing with governments) for over a decade.