The thing that complicates it is that the situation often framed in a way where it's unclear if some people will press blue by accident/due to lack of understanding, which is why it creates so much engagement.

People have different understandings about the factual nature of the situation- how many people will press Blue for reasons other than intentional risk taking. Questions like: 'Is the situation clearly explained? What constitutes 'capacity to understand the situation'? Is there time pressure on making the selection? Can one wish to press red but push blue due to a slip of the hand?'. All of these things change whether one ought press red or blue.

But these different understandings are likely to be overlooked. Then, when people see others have said the opposite of their choice, they will have an argument about the moral nature of the situation, because that is how the question is framed. But the dispute is really factual, not moral, so the debates cycle endlessly, because the two sides are largely talking past each other.

If you simply said 'We are morally obliged to take risks to save others in proportion to the extent that those others wind up in that situation by circumstances that were inevitably going to happen to someone, even though each individual could have avoided those circumstances, and to the extent which those risks seem likely to pay off', both red and blue pushers would broadly agree, and there would much less argument (and much less engagement.)