What's the difference? All have to live under central planning, all have to live with hubris of the rich and elites, at least Mars sounds way cooler than living in cities.
Musk wants to be a founding father. And just as the OG founding fathers, his problem isn't necessarily with the centralization part in general, but with the centralizing being done by others. There's a reason the original American voters were all white land owning men (and in some cases, slave owning men!).