>Why is this? None of us want this personally.
presuming the policy which is not fit your opinion don't reflect people's opinions is dangerous way.
I don't think it's unreasonable to assume the vast majority of people would prefer to not have trash in the ocean, all else equal. Trump conservatives are often stronger environmentalists than NYC liberals if that's what you're getting at. The garbage patch itself is a non-partisan issue. It's the methods and tradeoffs of getting rid of it that are partisan.