They tried. Their account was immediately censored/restricted.
The Facebook Coin Tweet is proof of the potential reach that is still possible with that account. The potential there is extraordinary with the right strategy, I have 0 doubt.
No, because the second they tweet anything about BCH, it's automatically restricted. The same thing happens on my Twitter account @pokkst when I include my website pokkst.xyz
So what? Even if that's true, they still have a Bitcoin Cash tweet pinned on there account. A viral tweet draws attention to your account and your pinned tweet.
I mean, Imagine @bitcoin regularly got as much engagement as the US President, as that Facebook tweet proved is possible. Think of all the attention that brings to the pinned tweet.