The article claims that the warming effect from bouncing heat back down is overall larger than the cooling effect from bouncing heat back up. If you disagree with this assertion, you'll need to say why, not just call someone a liar.
The article does agree that 9% of contrails have an overall cooling effect, and perhaps that could be magnified by a larger or more persistent contrail.
> The article claims that the warming effect from bouncing heat back down is overall larger than the cooling effect from bouncing heat back up. If you disagree with this assertion, you'll need to say why
I'm not sure they do. It's an extremely counterintuitive claim that would need to be justified, and while the author does cite (their own) paper, it sounds like the model they came up with is highly parameterised and not particularly physically validated. If it's really the case that contrails reflect more heat down than up (unlike what the scientific consensus says is true for regular clouds), then there should be an explanation for what contrail-specific factor causes this, not just "here's a pile of math equations that say it doesn't, don't ask where we got the parameters to fill them out from".
I'm not going to argue the point, I'm no climate scientist. But Wikipedia https://en.wikipedia.org/wiki/Contrail disagrees with you as well, so you'd need to argue with their sources too.
"In general, aircraft contrails trap outgoing longwave radiation emitted by the Earth and atmosphere more than they reflect incoming solar radiation, resulting in a net increase in radiative forcing."
Shiny bright light goes through or gets scattered. Dull red blackbody radiation gets absorbed. Doesn't sound too counterintuitive to me, but again I'm no expert.
The article does agree that 9% of contrails have an overall cooling effect, and perhaps that could be magnified by a larger or more persistent contrail.