i think it is pretty simple to discuss and even disagree on topics on the internet. here's a basic template for disagreeing with posts by people you do not know well, if at all, not containing vitriol or adulation:
hi, _____. it appears your view of ____________________
i debate and discuss and disagree with people on the internet all the time, especially on goodreads and on facebook. some i know well, some i know slightly, and some i don't know at all. i don't need to kowtow to express an opinion, and if i am enthusiastic it's because i want to be. i can't deny that occasionally it has got feisty or heated because that wouldn't be true, but i can honestly say it's never ended with me willfully refusing to understand the point of view(s) being expressed. asking that you show a little consideration and respect when you make a comment is not a debating point; if you can't come to any kind of agreement and it's clear that never the twain shall meet, it seems all there should be left to say is, thanks for letting me know you disagree, hopefully i can take your cues about further dialogue in future and get to know you better (if you are determined to continue to talk to these people you so vehemently disagree with), or walk away. or switch channels...
in fact, it seems to me that people become trolls when they confuse the internet with tv. people are used to spouting their opinions at their tv as they flip its channels. plenty of people watched LOST for example, and yelled at the tv "why the fuck am i watching you?", "you are stupid!", "i am turning you off because you are bullshit" but still kept watching every week. i've no doubt when some people continued to watch as they shouted "i am not watching you ever again! this is not an island show! every island show should have coconut phones and a skipper too" and then posted their disgust somewhere on the internet, if not taking the further step of placing an ad in variety, to let the producers know. but the tv itself doesn't care because it is not a person. and people think because they watch so much of it, they are entitled to give shit without respect. and since the tv can't reply "if you don't like what i have on, go watch something else." people have got used to giving to their non-responsive hardware the gears and brought this practice to the internet. if only it stayed there: again, i see nothing wrong with somebody shouting at their computer because of a comment they read on the internet: "good gravy, man, you're a moron!" but people on the internet can and may respond. they are not plastic cabinets filled with tubes and wires. navigating internet dialogue means understanding that people can and will reply to comments you make if they choose but the author can also choose to ignore you. trying to debate a request for civility or to refuse to agree to disagree because you wish to debate is just self-important and rude. it is like beating a dead horse. on dallas. i'm probably going to wake up in the shower now, and this whole thing will never have happened.