Group was polling to decide their official endorsement, calls out Sanders supporters on Reddit for brigading poll.

https://youngdem.com/topic/86065-youngdemcom-official-endorsement/

Edit: Reddit discusses

http://reddit.com/r/conspiracy/comments/43jgc9/youngdemcom_voters_endorse_hillary_clinton_isnt/

http://reddit.com/r/circlebroke2/comments/43jr6z/berniebros_try_to_brigade_an_offsite_poll_with/