'Bandwagon' is only a fallacy when we're not talking about something which is contingent on human views and behaviour. What people believe about the situation is a factor in how the game theory plays out, not just in DPOS but in all extant crypto financial systems.

You are saying that the same thing can happen in any hard fork, but it's not true. The viability of such an action is dependent on how participants view it, and people would view it differently than this situation.