Avoiding using the left/right terms because it simplifies a hugely complex set of behaviours, I think part of the problem is that the current global state of confected fear is pushing the average-joe to blaming all the ills of the world on 'the unfamiliar' (those who are superficially different by skin colour, language, culture, religion etc.).
The Bannons and Trumps of this world both encourage that fear and play up to the blaming of "the unfamiliar" because it is popular (populism?), and if nothing else, politics is a popularity contest.
Moderate folks aren't bombastic. People that believe in a cooperative society aren't bombastic. People that are scared of "an invasion of the unfamiliar" feel they need to be bombastic as "identity self-defence" - this is correctly categorised as 'conservative' because it's seen as a conservation of the status quo.
The biggest, loudest people seem to be those with the most to gain from a fearful, compartmentalised, under-educated society, and because of the loudness and bombast and overall 'theatre' that goes along with it, these people get more air-play than is representative of their numbers, but also more influence than is representative of their numbers - popularity plays (sells) in media, which flows into political influence.
The author is requesting better forms of discourse that don't play into the hands of bombast, which is essentially not possible, so the author then moves to a restriction of the air-play these loud minorities receive, which is what radiantswirl is saying, not incorrectly, is a conservative position. It's also just as impossible as improving the style of discourse.
What I see as the solution is that the moderates need to adopt the same strategy of theatre. It feels 'spinge-tingly icky' to suggest it, like marketing cigarettes and sugar to children, but if your message isn't getting through, then your methods of communication must change.
Climate Change, as a nicely divisive example. Would you believe Exxon (cue images of oil slick covered penguins), or BP (cue images of oil volcano in the Gulf of New Mexico), or would you believe what 90% of scientists are saying (cue images of clean, white laboratories with test tubes of bright colours and people with glasses in lab coats with clip boards).
Bigger, louder, you're-fucking-moronic-if-you-think-otherwise.
Moderate makes no headlines. Moderate is background noise; elevator-music. I hate the fact, but that doesn't mean it's not true.