Engineers get 20% time period. You can be asked to defer it for a quarter. On the other hand, most don't take it.
I don't know him personally but I read the stuff he writes, and while his character can be a bit abrasive he's an extremely intelligent dude who can make astute observations and connections that other people miss. I think you're doing him a lot of disservice by dismissing him the way you did.
(That's a trick question, since the answer is going to depend on the person's intelligence and ability to make observations.)
Also, a ton of long-time Googlers agree with the stuff he says. It's not like he's some lone dissenting voice.
Personally, I did have very soft discouragement against wide-open 20% time. I asked around and a lot of people I talked to initially advised me against starting a 20% project so early, and especially against starting a new project rather than working on an existing one with engineers at a higher level than me. At least, they said, make sure I could get reviews out of it. That's not policy, but advice. People have their own theories about how best to get noticed and get promoted. Some of that has to do with 20% time. I guess if you're solely interested in promotion then you give more weight to such advice. I hope most Goolger's aren't solely interested in promotion.
I'm very glad I ignored that advice, both because I got to do very interesting things and because I got recognized for it, and I'm glad that I could ignore the advice because of our policy.