I kind of disagree with this. If a company publicly claims to follow certain principles and vows to have mechanisms in place to protect user privacy, people on the inside are able to judge if those principles are being followed. The larger a company is, the lower are chances that everyone would stay silent in case of a (systematic) breach of those principles. So in a sense, it's much harder for larger companies to secretly do things simply because larger groups of people are worse at keeping secrets.