Do people who practice a religion that believes in reincarnation look down on mentally handicapped people?

Only an ignorant person would look down on a handicapped person as 'getting what he deserved' for wrongs done in a past life. A lot of people don't understand reincarnation, and your question brings to light one serious misconception many have about reincarnation and karma. Anyone who understands how reincarnation and karma really work would never look down on others.

In the first place, if an individual is disadvantaged in some way because of his karma, we respect him for his courage to take on the challenges that will teach him what he needs to learn. We have free will, and karmic situations are never forced on anyone. Secondly, not every disadvantage is a consequence of having done something 'wrong' in the past: we sometimes choose to experience difficulties and face obstacles that will challenge us - much like the reasons some people climb mountains - just to get to the peak, just to see the world from another viewpoint.

Thirdly, it's very common for an individual - especially a somewhat advanced individual - to take on certain life challenges in order to teach others. This is a very selfless, loving thing to do. Helen Keller, for example - blind and deaf since early childhood - inspired millions of people and taught us so much about the strength and wisdom a seriously handicapped individual can have.

The smart Reincarnationist sees "special people" as very special indeed.

As a Christian i'm no longer meant to have faith in reincarnation. yet whilst Jesus asked his disciples approximately who people concept he became one reported they concept he became the prophet Elisha who had lived long earlier Jesus became born. Jesus would have set the record at cutting-edge then and there asserting that reincarnation isn't attainable. yet he did no longer say that. So who am I to assert it can't or would not ensue?

Some do yes, but any Buddhist who does in not being a very good Buddhist. Buddhist compassion is not a condescending compassion.

handicap people are exempt i think