I don't disagree with the sentiment, but I do disagree with your reasoning
Personally I don't vote for what affects my life in the most positive way, because that seems a little selfish although it's understandable.
I vote for what I believe affects everyone's life more positively, even if it's not necessarily a benefit to my specific situation. I might not be gay but I would vote for the candidate who supports gay marriage vs the one that might give me a $1000 check for tariff profits.