[oldbrowser]

"Your votes will either help or hinder the winning candidate."
My vote will help the candidate I vote for, and be an equal hindrance to every candidate I don't vote for.
Let's call it a missed opportunity vote. It is similar to not voting at all, your one non vote could have helped swing the victory to an unfavorable candidate.

"You personally will be partially responsible for the winning candidate."
Doesn't follow.
I just hope you can live with yourself.

[Know your rights]

It [voting third party] is similar to not voting at all,

Not at all ... in the former case, my voice is heard.

your one non vote could have helped swing the victory to an unfavorable candidate.

The odds of my one vote deciding the outcome are about the same as my odds of being killed by a meteorite, and I give them comparable weight when choosing my actions.

I just hope you can live with yourself.

Quite well ... which is more than I could say if I voted for a pro-"choice" candidate.