Thank you for explaining.The tweet reads:
Satan is the best friend Kanye has ever had, as he will keep him in business all these years!
— The Church Of Satan
It is a twist on a quote by their founder Anton Szandor LaVey, who said that “Satan has been the best friend the Church has ever had, as he has kept it in business all these years.”
The vile claim is that since God does not exist it is the belief in Satan that keeps the Church alive, and now that Kanye is a Christian and will only make Christian music the same applies. I wouldn’t say they are pleased with it, just using his game to promote their cause.
These guys don’t actually believe in Satan as a spiritual being, but rather is a name for societal evils. Of course they are in service of him, just to ignorant to realize it.