You can’t grant access on iOS “to view / edit / delete all/any data”, that’s physically not possible, even with the hidden SDKs that only select parties have access to.
It doesn't change the fact that tracking your detailed location and who you are around in combination can be used to determine your affiliations or sexual orientation. If you, with your secure iPhone, are located around numerous people with Grindr installed, they may jump to conclusions.
They are capable of targeting gays or political opponents with this, which is the point of the story.
I heard of a software called Pegasus but couldn't tell if it was legitimately that powerful.