It's not about enforcing our opinions. It's about this:
Right now, a lot of people up/downvote content based on whether they agree or not.
I don't think I need to argue this point, to you, at least.
Visibility is based largely on upvotes and downvotes.
Therefore, people should be voting based on whether something deserves visibility, NOT whether they agree. But because people aren't doing this, the voting system just ends up becoming the circlejerk system.
My thought was, if we had a separate 'like' feature, people might realize that they shouldn't be voting based on whether they like a post, they should be using 'like' for that instead, and use votes to control visibility.