Everyone admits that the Google/Blogger decision to support Atom exclusively is controversial. Many even go so far as to claim the Atom move has split the blogging community.
A recent ZDNet article looks at both sides of the issue. On the one hand, "The Blogger decision to offer Atom only has angered supporters of RSS, who accuse Google of helping to splinter a wide network of RSS-using bloggers." There is also considerable criticism of Blogger for not at least supporting RSS and Atom concurrently.
However, the move makes sense as a long-term strategy when you start to look at what open source really means and where Blogger want to be a year or so down the road. And don't just think "Blogger." Think other Google products --even ones that don't yet exist.
"RSS has long been controlled by a single vendor or entity," said Mark Pilgrim, an early contributor to Atom. "Atom's an open standard, so people can point at the spec and say they're conforming to it, and it's not controlled by one of their competitors. And RSS is. It's no surprise that the vendors in control of RSS are upset about this. Open standards benefit everyone but them."