Slate often contains links to news sites, and does make its readers aware of facts, but is not a news site per se. It's really more of an opinion site, or a magazine (as the bar at the top of your screen will tell you).

The reason Google seems to like Slate probably has more to do with the fact that Slate has several articles this week about the current topic. I doubt they would rank so highly on a lot of other subjects (but for all I know they might).

The "bias" you refer to, if anything, is probably that of William Saletan (the author of the article). He also, I'd guess somewhat confusingly for new readers, refers to himself as "Human Nature," which is also the name of his column/blog.

In this article, he did link to some actual news sites, which wound up in the C&P section of your post. The arguments made come from the respective news sites, although Saletan does like to summarize them in very terse and sarcastic ways.