why are they still doing these
Because Clinton has failed to clinch the nomination yet and it's almost June lol.
Obama did not clinch the nomination while running virtually unopposed in 2012 until sometime in April. Romney didn't clinch it until June of 2012. Trump has yet to clinch it.
#Math
It's called having a 50+ point lead a year ago and blowing it, the comparison you use with others is completely irrelevant. Also this same poll has her unfavorables at 59% and Bernie's at 43% but yes she is obviously the better candidate. 
I kinda hate that logic. While Hillary did have a 50 point lead, she didn't lose 50 points. Hillary was always polling between low 60s and high 50s. There was plenty of room for a challenger.
