I think the president invoking the massacre of children to essential say the Republicans need to accept his terms of surrender in the negotiations is not just a non sequitur, I think it's sacrilege. And it's of a piece with the whole tone of his news conference and this is the way he conducts them generally, which is he is excessively self-righteous. He talks about the other side of being unprincipled, not interested in the national interest, slaves of ideology which he says makes no sense. And as you mention, invested in opposing him to the point they are willing to let the country suffer.

So it's a combination of self-righteousness and narcissism.