What exactly do people view as "wrong" about building a company to sell? Companies are sold because it's in the interest of both parties involved in the transa

What exactly do people view as "wrong" about building a company to sell? Companies are sold because it's in the interest of both parties involved in the transaction, so it must serve some legitimate function in the economy. Perhaps it's a little different if they're bought by a larger company only to eliminate the smaller competitor, but I doubt that's why buyouts usually happen. It seems really silly to me to criticize someone for wanting a high payoff to labor ratio or not wanting to dedicate their life to everything they do, but I don't know - what's the reasoning?