Keith is a decent enough bloke whom I've met.

That shouldn't be read to mean that the fact I've met someone in itself means they are OK. I've met some people I would not say that of. But when we get in an argument with a faceless stranger on line it's too easy to build up some picture of a kind of malevolent worm who should be expunged. In a way that's one reason the term Troll has emerged. Meeting people gets in the way of that process.