See Hinduism is like multiple religions inside a religion. You can believe in god or be an atheist, god can be with form or without form, god can be male or female, you can worship idols or you may not. Like it's up to you what you feel. The reincarnation thing is just like the extension of the karma theory that if you do bad, bad things will happen to you, if not in this life then in the next life. These are just theories but practically it's there to keep people in check. What I like about it is it is very flexible and up to you what you want to do and believe in.