Often a question arises for a Dalit - If Hinduism treats them as outcasts, then which religion would they chose. The options for some are Christianity, some are Islam and most are Buddhist. So why choose Buddhism. It is not my intent to insult any religion and I am only outlining what is already said in religious books. I also apologize if this post comes across as offensive or divisive.
On closer inspection of Islam, one thing that is disturbing is the Islamic Hadiths that talk about the whiteness of the prophet. If you look at this link it talks about all the Hadiths extolling the fair complexion of the prophet to a great extent
Even in today's world, Islam has different sects and some Muslims are treated inferior to others. Though this might be a generalization, Arabs have a history of looking down upon people who are from Africa and the subcontinent (even if they are Muslims). Read up on evidences of maid torture to learn more.
Another disturbing thing about Islam was that there are specific verses that talk about owning slaves in a war and mistreatment of non-believers. Owning slaves is never a good thing. Irrespective of whether it is a powerful Dalit or Brahmin or Muslim or whatever, you cannot be allowed to hold slaves. Slavery is bad no matter who does it.
Another disturbing thing about Islam was that there are specific verses that talk about owning slaves in a war and mistreatment of non-believers. Owning slaves is never a good thing. Irrespective of whether it is a powerful Dalit or Brahmin or Muslim or whatever, you cannot be allowed to hold slaves. Slavery is bad no matter who does it.
The Buddha was an enlightened soul who gave up everything to extol the virtues of peace and kindness. He never spoke about war, never spoke about having slaves. He spoke about compassion and peace, even to his worst enemies.
In today's India when Dalits look upon the ills of Hinduism and decide to leave the Hindu fold, Buddhism should be the only logical choice. Buddishm was most appealing to Babasaheb because his teachings fall right into place given our geographical and cultural context.