I've been struggling to compose a reply to this thread, because there is one thing LT has right (although in his typical fashion he isn't expressing it clearly): online interactions are relatively impersonal compared to 'real life' interactions, and as a result when online interactions go awry I think the risk for decorum to devolve is higher. I think that much is nothing new-- it's a characteristic of trad forums dating back as long as I can remember.
I also think that forums tend to attract people who have fewer opportunities for ('irl') fulfilling relationships with other good Catholics. Ask anyone what they get out of forums, and part of the answer will be solidarity. It's hard, to say the least, to go through life without Catholic friends. The Church is a temporal (although not only temporal) society, after all. Anyways, the point is that forum user bases already tend to be populated at least in part by people who don't have Catholic social lives, and that can compound the risk of vitriol. By the way, I acknowledge everything Matthew said as true, and don't mean to imply anyone is 'guilty' of having few Catholic friends.
But even with all this said, forums are by no means 'unnatural.' In principle it's just like letter writing-- where ideas tend to reign over rhetoric, anecdotes, and other personalized or otherwise less logical ways of communicating. And that is precisely their strength--at least theoretically, supposing that passions are controlled and those involved are willing to put in the work to THINK rather than intuit through issues.
Which kind of brings me to 'the point', as far as you go, LT. It sounds like your problem with forums is that whatever rhetoric and intuition you use in your daily life to convince people of a, b, or c just doesn't work on forums. Because it isn't intellectual. And by 'not intellectual' I don't mean 'stupid,' I mean it literally: it has nothing to do with anything that can be grasped by THE MIND. There's been a debate (if we can call it that) for something like two weeks now that literally hasn't gone past square one because you constantly repeat the same claims based on some close-to-inexplicable combination of projection, family history, and intuitive experience. It's so messy you can't even explain it well yourself, and I don't think even you know how to argue for or explain your claims. So you just draw the conclusion that it's everybody else's fault for not believing you, as well as the Internet's fault in general for being a platform that doesn't allow you to channel whatever rhetoric you normally find effective in your daily life.
That's what it seems like to me-- I can't really find another explanation for the way things have gone, though if anyone has one I'm all ears.
Long story shorter: you've got a point but the point isn't all that relevant to the exchanges of recent memory.