A quote from an article from before the vote:

Mr. Groen said he is a fan of both Mr. Ellison and Mr. Perez, the Obama administration's former labor secretary -- but the pro-Ellison effort convinced him to go public with his support for Mr. Perez.

"Let's say you were completely uncommitted," he said. "You don't want 300 people calling you and telling you what to do."

Definitely don't elect the guy with the engaged grassroots base. Smart.