It was a normative statement I believe ("companies should not be people and should not have rights") rather than a factual one (I'm sure they're aware & that's why they felt compelled to make the declaration). English is sadly lacking in this regard, where you often get to make a strongly worded statement or an unambiguous statement, but it's very difficult to do both at the same time.

The funny thing is that corporations have a bunch of advantages like limited liability on top of the US Supreme court ruling them to have the same rights as people, which means that corporations actually have more rights than regular people.