I think the goal was to have a good time in the afterlife. And I guess by disturbing their graves we've prevented that from happening :-) Or, they had already enjoyed a few millennia there and don't mind the change...
On a serious note it is surprising to see them just let large groups of people in to touch and snap pictures
Bottom line, though, was that survival in the afterlife depended on the integrity of your mummy. They removed the brain and internal organs because mummification didn't work, otherwise.
https://en.wikipedia.org/wiki/Book_of_the_Dead
The British Museum had an amazing exhibition about this several years ago.
[0] assuming the arrow of time is irreversible [1] https://en.wikipedia.org/wiki/Information-theoretic_death