"Dems"

I saw the above on Memorandum this morning. It's a strange headline because Sanders, although he serves in Congress as an Independent, is running for the Democratic Party nomination. So how could "Dems" view him (or O'Malley for that matter) as a threat? His supporters are Dems!

Luckily the Politico article behind the link has a different headline. I'm not sure who wrote the Memeorandum link. They are supposedly automatically generated, so I wonder if that is what Politico calls its article in an earlier version.