I'd offer to buy him or her a drink at the Connaught. My favorite hotel in London, btw. The Lanesborough is a close second.
Because IRL conversations tend to be more civilized. I did something similar with my political opponents on two separate occasions; I met them IRL at an upscale public space.
Hopefully I'd be able to convince him or her, at the very least, that not every incel is an unemployed pasty white high school dropout from middle America who never showers, lives in a basement, and subsists on a diet of Doritos and Mountain Dew.
Because there's nothing more ridiculous on IT than that assumption, and it's the one that I can't wrap my head around. I can't help but feel that it's a crude stereotype to mock men who are unlucky enough to live in economically depressed areas.