Yes it does matter if the moderate swing voters see it as too far left. Better to win with a candidate you agree with on 90% of the issues than lose with one you agree with on 99% of the issues.
The issue being that for many of us anti Hillary supporters, she really doesn't agree with even that 90%, or atleast has not supported a ton of it until this election cycle until she started attempting to walk back a lot of her previous rhetoric and support of horrible causes.
That's why i am against your view that supporting someone like that over someone i support more on the issues is better. Bernie Sanders to me has been far more consistent and what he believes in than Hillary.
It doesn't matter if its 90% or 99% of the issues if its not something they really believe right? I'm not optimistic enough anymore to believe only in what comes out of a candidate's mouth during election season when their track record proves otherwise, and the people they are getting support from are more in their interest.
You know the phrase "don't let the perfect be the enemy of the good?" Well i believe in that.
Bernie is not a perfect candidate by any means. He's had suspect votes on gun control representing Vermont which he has had to defend, as well the fact that he's not yet outlined how he would go about securing votes from conservative Democrats in order to pass his legislative proposals.
But i'm willing to pass on that because i believe he actually cares about the issues he has consistently supported, and feel that a strong will and actual honesty is important to representing the interests of this country.