Yes, this sort of thing has been going on for thousands of years. The Muslims of today are the descendants of the worshippers of Baal in ancient times. When Mohammed came to Medina, the peoples of that area were Baal worsippers, Baal being a moon god, which is why mosques today still have the crescent moon on top. Their cutting themselves is even mentioned in the Bible--
1st Kings 18 25-29
25: Then Eli'jah said to the prophets of Ba'al, "Choose for yourselves one bull and prepare it first, for you are many; and call on the name of your god, but put no fire to it."
26: And they took the bull which was given them, and they prepared it, and called on the name of Ba'al from morning until noon, saying, "O Ba'al, answer us!" But there was no voice, and no one answered. And they limped about the altar which they had made.
27: And at noon Eli'jah mocked them, saying, "Cry aloud, for he is a god; either he is musing, or he has gone aside, or he is on a journey, or perhaps he is asleep and must be awakened."
28: And they cried aloud, and cut themselves after their custom with swords and lances, until the blood gushed out upon them.
29: And as midday passed, they raved on until the time of the offering of the oblation, but there was no voice; no one answered, no one heeded.
You do realize he was kicked out of Mecca for trying to abolish such religions, don't you?
Besides, you need to narrow down which Ba'al you're talking about. The word basically means "lord" and as far as the Arab worship before Mohammed is concerned can apply to any of the myriad gods the idols of Mecca and Medina were set up for. If you mean Baal Hammon (known for child sacrifice, etc.), which some take to have been a moon god, that's a different god worshipped by the Carthaginians, long before Mohammed and far away from the Arab areas.
BTW, about that crescent. It may have been used in relation to Ba'al Hammon, but that is not the source for Islam's use. It was also used with a star by the Christian Byzantine Empire, with probable pagan origins. The Ottomans adopted it after they conquered Constantinople, and it has been used by Muslims since.
Mohammed himself preferred a banner or flag with script glorifying Allah, and many Muslims reject the crescent as a pagan symbol.
Fascinating, Captain. And Baal worshippers were intoshild sacrifice and child sexual abuse, also abuse of women, Temple Prostitutes, sacred groves, that sort of thing. So, it should be no surprise that Mo took a nine year old as a slave err... wife.
 And Elijah said unto all the people, Come near unto me. And all the people came near unto him. And he repaired the altar of the LORD that was broken down.
 And Elijah took twelve stones, according to the number of the tribes of the sons of Jacob, unto whom the word of the LORD came, saying, Israel shall be thy name:
 And with the stones he built an altar in the name of the LORD: and he made a trench about the altar, as great as would contain two measures of seed.
 And he put the wood in order, and cut the bullock in pieces, and laid him on the wood, and said, Fill four barrels with water, and pour it on the burnt sacrifice, and on the wood.
 And he said, Do it the second time. And they did it the second time. And he said, Do it the third time. And they did it the third time.
 And the water ran round about the altar; and he filled the trench also with water.
 And it came to pass at the time of the offering of the evening sacrifice, that Elijah the prophet came near, and said, LORD God of Abraham, Isaac, and of Israel, let it be known this day that thou art God in Israel, and that I am thy servant, and that I have done all these things at thy word.
 Hear me, O LORD, hear me, that this people may know that thou art the LORD God, and that thou hast turned their heart back again.
 Then the fire of the LORD fell, and consumed the burnt sacrifice, and the wood, and the stones, and the dust, and licked up the water that was in the trench.
 And when all the people saw it, they fell on their faces: and they said, The LORD, he is the God; the LORD, he is the God.
1st Kings 18 25-29
My absolutist, favoritist "Bible story".
Every time I read it, I laugh myself silly, imagining Elijah goading them on to ever more strenuous efforts to "awaken" their "sleeping god", while they rant & implore; hack, stab, & slice themselves; and finally, huffing & puffing, slowly run out of steam, and drop to the ground.
If their tongues hadn't already been dragging the ground, a few of them might have managed to out run the crowd after the Heavenly Fire consumed Elijah's sacrifice, meat, bones, hide, alter, water, and all.