There's no point 'debating' with deniers, no matter what persuasion they are, whether they're denying due to their politics or their religion, or just through peer pressure.
Everyone these days seems to stick to their guns and get abusive and intransigent. What to do but to write a limerick? - see below:
Alas, it's become a lame ruse,
to doubt what offends you and choose
to question elections
and vaccine injections
and label the truth as fake news.
Below are links to my Global Short Story Competition winning story, my short-listed story for the National newspaper and a story that appeared on the Every Day Fiction site - where you can leave a comment:
http://www.thenational.ae/arts-culture/short-story-a-day-for-decisiveness
https://everydayfiction.com/respecting-the-dead-by-paul-a-freeman/
Happy writing!