Note that Apple is working to restore that content to past purchasers, but ultimately, it's up to Disney to allow it.
The way the iTunes Store works for movies is that you buy a digital copy, which you may stream/download from the cloud as many times as you like (to authorized devices), as long as that content remains in iTunes. For this very reason, Apple recommends making a backup of any digital copies you buy, in case that title ever gets removed from iTunes by the owner/distributor.