UX is orthogonal to the thing most web-based software companies optimise for. Unless users are paying for the service, what the company cares about is user engagement, not user experience. It's not that every software company ever doesn't know what they're doing, it's just that what they're doing is _at best_ tangentially related to improving UX. It is clearly not in the user's best interest that they feel compelled to check Facebook frequently throughout the day, or spend hours scrolling through their feed. You can spin that as the company just improving the experience so that people want to keep using it, but fundamentally it is intentional psychological manipulation.
Within a university, research with human subjects is required to pass an ethical review before it is allowed to proceed. Given the scale and impact of the research conducted by Facebook on its users, it is entirely reasonable to hold them to the same standard.