Well, since most of human nature tends to side with the forces of good over evil, Satanism is probably very much a fringe religion with very few actual participants.... so no, they don't have the numbers or the power to do much of anything as dramatic as genocide.
Truthfully... All genocides are not of God, they are of man. Even the ones done in God's name. Man is his own worst enemy.
As I don't believe in god or satan..then genocides get attributed to causes, factions, political beliefs, ethnicities, religions or nations in my world.
Christianity, thus far, holds the record for genocides in this regard. The other big two are distantly behind that religion.
But it's interesting that "Satanic" worship gets the blame for the world's "evils".
Especially given the propensity to "purify" souls via "releasing" them. No?
Early so called Chritians did evil on their own not because of the belief in God. Let me quote Jesus.
This is a parable explained.
Mat 7:14 Because narrow is the gate and constricted is the way which leads to life, and there are few who find it.
Mat 7:15 Beware of false prophets who come to you in sheep's clothing, but inwardly they are ravening wolves.
Mat 7:16 You shall know them by their fruits. Do men gather grapes from thorns, or figs from thistles?
Mat 7:17 Even so every good tree brings forth good fruit; but a corrupt tree brings forth evil fruit.
Mat 7:18 A good tree cannot bring forth evil fruits, nor can a corrupt tree bring forth good fruit.
Mat 7:19 Every tree that does not bring forth good fruit is cut down and thrown into the fire.
Mat 7:20 Therefore by their fruits you shall know them.
Mat 7:21 Not everyone who says to Me, Lord! Lord! shall enter the kingdom of Heaven, but he who does the will of My Father in Heaven.
Mat 7:22 Many will say to Me in that day, Lord! Lord! Did we not prophesy in Your name, and through Your name throw out demons, and through Your name do many wonderful works?
Mat 7:23 And then I will say to them I never knew you! Depart from Me, those working lawlessness!
Mat 7:24 Therefore whoever hears these sayings of Mine, and does them, I will liken him to a wise man who built his house on a rock.
Mat 7:25 And the rain came down, and the floods came, and the winds blew and beat on that house. And it did not fall, for it was founded on a rock.
Mat 7:26 And everyone who hears these sayings of Mine and does not do them shall be compared to a foolish man who built his house on the sand.
Mat 7:27 And the rain came down, and the floods came, and the wind blew and beat on that house. And it fell, and great was its fall.
Mat 7:28 And it happened, when Jesus had ended these sayings, that the people were astonished at His doctrine.
Mat 7:29 For He taught them as one having authority, and not as the scribes.