Well, it not only that, but Hinduism is inherently syncretistic. Somebody (Peter Kreeft?) wrote that, if you try to tell a Hindu about Jesus, they're likely to say, "Oh, yes ... Jesus was God Incarnate? ... just like all of our best gurus!" The idea that the Incarnation was special and unique is foreign to them; their religion teaches that incarnate gods are commonplace.
I wouldn't draw too many conclusions about anything from an Indiana Jones movie ... I used to call them "Steven Spielberg mocks the world's great religions, Parts I, II, and III". (I have no idea what the last one was about.)
A non-Christian might suppose from Indiana Jones that Christianity is mostly about a knight guarding a table full of cups in a boobytrapped cave in Jordan.
1. I know. Sidhartha Gautama, the Bhudda, was deified immediately by the Hindus even though he (reportedly, since there was no Indian writing at the time, all oral history) repeatedly told the people that he was not God or a god.
The Hindus have some 330 million gods. My husband was SURE that somewhere in India there were Hindus worshipping a '56 Chevy. Nothing surprises me about Hinduism.
2. I don't. In my opinion Spielberg sells movies and he'll sell whatever the market is buying. Anti-religion sells in Sleezywood cuz it validates their sleezy way of life.
3. I think non-Christians know as little about Christianity and Christians know about Hinduism or other faiths. Some hardly know their own faith. Ditto for most people, I think.