Edge has vertical tabs out of the box. And yeah we get it, because vertical tabs people and tree tabs people are the vegans of browser discussions. Please, we get that you like vertical tabs. No need to keep going on about it.
'unless you've seen someone' is not a good standard to use here, because of course some people are like that, that's where the stereotype comes from - but the vegans who don't 'keep going on about it' are inherently not as visible: it's not often you'll know someone is a vegan and not talking about it, essentially never for strangers.
So if you really care about reasoning with people to challenge the stereotype, you need to know % vegans (according to some survey or whatever) in a population relevant to a person so that you can ask them to consider not if they've ever seen one vegan talk about it, but if they've seen a number X close to that % of the total people they've seen talk about it (and if not that they've encountered that-X% extra vegans without realising it).