Everyone's in an echo chamber to some extent. But beyond that, I don't see that as a "real" question. As in, I can encourage Dudebros or hardcore Christians to be 'better,' but there's nothing I could say to make them do so, and it's frankly a waste of time to try. I don't go onto Geeks & Gamers to tell him his takes are terrible, I don't go into Evangelical churches to say "hey, maybe homosexuality isn't a sin," because I'm just one person, and nothing I could say could convince these people otherwise. Besides, LGBT marriage was solidified by plebicite here, so any such people whining about it are in a distinct minority.Dudebros and Christians are told they should hate LBGT. That is true. Should we leave them in an echo chamber? Or maybe we should encourage something better?
Point is, if someone's that far gone, it's a waste of time to convince them otherwise, and if you could convince them otherwise, I'm not the person to do it. Homophobia isn't based on reason anyway, it's prejudice, all the reason in the world isn't going to convince a wanker.
(Also, since I'm apparently now obliged to do this, "not all Christians," "not all Dudebros," etc.)