Changes in the DVD version

Why were these considered necessary? Why should a studio-released motion picture bring anything to bear on the original material?

Example: At the end of The Purge, the custodian in the tank, repetitively pulling the lever, is changed to show the outline of Aeon herself. Why did they feel it necessary to hammer this conclusion home? The Purge as an episode is surreal, more so than most, and fairly inscrutable. Why alter this part?

Example: Trevor's voiceover at the end of Reraizure is changed. It originally read, "That's the funny thing about memory, isn't it? We are not what we remember of ourselves; we are what people say we are. They project upon us their convictions. We are nothing but blank screens."
In the DVD re-release, this was replaced, using the voice of an older John Rafter Lee, to "We are not what we remember of ourselves. We can undo only what others have forgotten. Learn from your mistakes, so that one day you can repeat them precisely. Stop. Erase."

There's more. But why?

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