This hardly takes any genius to figure out. Centrist literally results in what she does, and it's seen only as a negative (and never the positives) in the eyes of the easily influenced through propaganda. Likewise, you were just praising Sanders for being idealistic, which is a narrative the GOP is also pushing to sow discord within the enemy camp. If Sanders were the candidate, they'd be pushing his leftist socialism angle which I gather you're not a fan of, and the gullible dimwit take on the matter would predictably reflect that.
Worth noting that I wrote the paragraph above before the post it replied to. That's how predictably dumb these dimwits are.
The fact the dimwits don't criticize Obama for the same centrist witch flaws perfectly illustrates the situation.