A cursory first read shows glossing over two big issues (probably more, but these two stood out):
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1--Algorithmic manipulation ... despite claims of good intentions, any time we defer timeline content selection to software, we're really saying that we trust the software's creators and operators to decide what we see or don't see. On many issues, there is no unified and settled truth, so the deciders would have to enforce their own biases.
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2--The "Uncle Fred" problem. Every one of us has contacts that hold some wacky beliefs. Just as we remember being uncomforable at family events after an uncle had a few drinks and his tongue loosened up, choosing to display or block content based on what our contacts did subjects us to the Uncle Fred contacts again.