I can’t disagree more with your majoritarian arguments. You (and I) would probably object when, e.g. California voters ban gay marriage. But you cheer when slim majorities attempt to saddle others with heavy economic burdens or interpose themselves in others’ contractual arrangements. I find most democratic decisions illegitimate; how hard is to to just keep your nose out of other people’s business?
The founders were aware of urban/rural tension from the beginning. The system was designed to make it difficult to force obligations on fellow citizens. That means majorities are being thwarted in their efforts, and that’s a good thing.