It absolutely becomes everyone else's problem when they start shooting people or seizing control of things they're not supposed to. If you wait to the point that it affects you personally, it will probably be too late to do anything about it. Refusing to believe in something doesn't immunize you from force wielded by people who do believe it.
Once the aggrieved-in-chief victim of the century is out of office, the theatrics around election fraud will cease.
We could all hope so, but this is a very passive response. Do you really think the people in the President's orbit are unaware of his advanced age and declining health, or are willing to just return to private life and give up power once he dies of natural causes? It seems far more likely to me that they know he could go any time and have some sort of plan to stick around. While none of them have exert the same sort of charismatic influence as the President does, do you really imagine that they and the substantial bloc of voters behind them are just going to magically come back to their centrist senses and abandon their violent and paranoid ethos?