If it weren't for indignant threads in cycling forums publicising this loon, no one would ever read his tripe.
He's quite the chatterbox under his various sockpuppet identities on twitter and is often found being 'angry of Tunbridge Wells' in the comments and letters pages of local newspapers where driving/cycling stories appear. He also didn't spring unbidden as a response to cycling forums or social media posters, he popped up all on his own to propagate his strange world view.
But yes, he would have a lot less followers on social media and less clickbait hits for his internet presence if people with a differing viewpoint simply ignored him, but so would the Daily Mail and its reactionary ilk.
Those that do engage would argue that sentiment like yours and mine of ignoring his ravings and letting him go unchallenged validates to him and those of a like mind that they must be right, so they have to follow/find his stuff to respond to it. Not convinced on that myself, I think he's one of those that gets off on the conflict aspect as much as anything else he may do it for.