Many governments have been built in ways to try to mitigate this. For example, in the US we have the electoral college and the Senate (where each state has an equal vote). Not saying I support the electoral college (I don't), but at least there's some thought behind it...
Another example is the parliamentary system where each party gets some type of representation in the government and where absolute majorities are rare.
Point being that governments, while democratic in flavor, have implemented some safeguards against this type of tyrany of the majority.
Not sure if I necessarily agree that the issue we face in the US has to do with "tyrany of the majority", but even if it does I would never claim that the system is perfect, hence the "try to mitigate this" part of the statement above.
Another example is the parliamentary system where each party gets some type of representation in the government and where absolute majorities are rare.
Point being that governments, while democratic in flavor, have implemented some safeguards against this type of tyrany of the majority.