They may have been the start of the sell offs but they alone are not the entirety of the volume on exchanges. It's annoying their pissing contest moved the market so quickly but it does look like the cycle is about complete.
That's how the market works, unfortunately. Buy the rumor, sell the news, and their shitting contest is all over the place, so we can't do much about that now. The bears have already capitalized on that particular news and have been doing bull traps all over the place to keep on profiting. Even the weak hands--understandably--are already letting go of their prized coins just because they're scared of bitcoin's value going nil (which isn't going to happen anyway). It's just crazy how a fork of a fork affect the entirety of the cryptomarket, and the pissing contest between these two crazy guys are changing the tides of the market without them even lifting a finger.