Why are there no black or asian riders on the Tour de France?

Between 1910 and 1920 two Africans were brought to the Tour de France to compete, and for many days they hammered the competition. This was back in the days when slipstreaming was seen as cheating, and each rider rode solely for himself. One of the Africans had to drop out through illness, but the other kept a huge lead over the opposition.
At one point he ran out of water, and was passed a bottle by a spectator. The rider necked the lot, only to discover it was wine. The rider was Muslim, and had never drunk alcohol in his life, so the vino pole axed him. The spectators caught him as he fell, and realising he was pissed, laid him under a tree to sleep it off.
By and by the other races caught up and passed the sleeping African, and the crowds drifted away.
Hours later he awoke.
It dawned on him what had happened, so he leapt on his bike and raced off in pursuit. He pedalled furiously, but failed to catch any of the other riders.
Why?
In his befuddled state, he set off in the wrong direction.
If it wasn't for one bottle of wine, then an early Tour winner would have been African, and with him as a hero, the face of cycling would have (literally!) been changed forever.

You're wineing us up with that story.