Their response is not irrational. They feel unrepresented by the system, so they would rather let it fall to pieces and fight, if it comes to that.

Except I was feeling them out for what is their ultimate goal, and at no point did they say anything about the whole system falling apart. You are trying to rationalize their actions, but it is, frankly, just irrational. But even if it were "let the whole system fall apart" that's also irrational because, chances are, it's not them that is going to come out on top. It will continue to be people who currently have the power.

The difference is that you wish to win, following the rules of the game. They want to change the game

Not mutually exclusive. I understand the game I am playing, and play with those rules, and act rationally within those rules. I understand that you don't change this by voting third party for president. I know that might feel good, like you are doing something, making your voice heard. But it's just pissing in the wind. If one wants to change this, it comes from the floor up, and it's something I do push locally as well.

In any case, rationality is often the enemy of action. A thousand people waiting until they have the definitively right direction end up doing little.

We do know the way forward, it's working from the ground up. It's getting our election system changed. No single president can change this, which is exactly why protesting the presidential election in this way is pointless.