FaceDeer , 8 hours ago

If you simply don't want to engage in a discussion with him, then that's fine, you should let him know that you're not interested in talking about it. You don't have to justify your choices to him, if you want to use a particular browser then that's fine and if he spontaneously decides he needs to "talk you out of it" then that's a dick move. Tell him that you don't want to debate the subject and it's no skin off of his nose so he shouldn't try to engage you in one.

But if you're asking "how can I convince him that he's wrong", well that is engaging in the debate. And if you're going to engage in a debate you should try to be as open about it as you'd like your debate opponent to be in turn. Have you considered that perhaps he has some valid points and is not taking that position just to be contrarian?

Personally, I find that it's pretty much impossible to talk someone with a strongly-held position out of that position. The value of Internet debates with people like that is that lots of spectators who don't have such strongly-held positions may be watching, but when it's a one-on-one situation it's likely to be a futile and frustrating effort with no benefit. So I would advise going with the "don't bother engaging" route. But of course, if you feel strongly that you want to engage, I can't change your mind on that and won't try. It's your time to spend.