Because, debates occur from the ego mind. Which is a hodge podge of mental nonsense. Even the Guru stated that all these so called debaters, priests, learned people are deluded and corrupted by Maya. So why debate with them? Maharaj selects his Sikhs, in this world you are either the real deal or just a pretender. Debating with a Muslim would get you nowhere, except maybe a trip to the drugstore for some Tylenol. They are just so rigidly ingrained in their beliefs, not an iota of spiritiuality is within these debaters. To understand me you need to understand the difference between the ego mind and the Universal mind. We don't need Sikh converts, we don't need Sikhi to grow in numbers, it is the Truth, and the Truth (capital T) will stand the test of time. As for why these religons exist, only Mahaakal knows... my guess is they come from the underworld. Lol