You do realise that most functional democracies are consensus based, and not based on 51 % ruling 49 %?

In a functional democracy, you have representatives of various groups forming coalitions, such that most cases are passed by a relatively large majority. Of course, some stuff is pushed through by a slim majority as well, but if it's sufficiently unpopular it'll just be reversed after the next election cycle. In most cases, the part(y/ies) that hold the majority seek support from at least one opposition party to ensure that their bills aren't immediately reversed once they lose power.

Consensus is at the absolute core of a functioning democracy, just not the absolute consensus that anarchists for some reason push for. You can't have one person in a population of millions blocking a resolution. What about ten? One thousand? A well functioning democracy naturally finds this limit through the formation of coalitions that pass bills with a broad enough consensus that they more often than not survive when power changes hands.