The only hint of anything socialist in this report is that Japanese zoning is based on centrally planned guidelines. However, the author reports a key downside of this: that there are fewer possibilities for experimentation- so I don't get that this is left-leaning.
> just because there is an open area available, should we really develop everything
The author makes the point that whitelist-based zoning results in urban sprawl. So, IMO, if you are going to develop an area, make it dense, convenient, and creative. And then you can leave the rest undeveloped. I don't know about the zoning laws in Seattle, but it's pretty dense with residential towers, pretty mixed use downtown and in Capitol Hill, but hikes and waterfalls are like a 20 minute drive away.