Ligament, Schligament....

What is really wrong with static stretching?

Relatively speaking, muscles can recover from being stretched repeatedly.  However, ligaments can not easily recover from being 'stretched'.

When a ligament is stretched to the point of being loose and flexible, the surrounding muscles have to 'take up the slack' and re-actively tighten up to stabilize the joints/structures.
And, the more you stretch the ligament(s), the more the muscles re-actively tighten up.

So, while stretching might loosen you up for a few minutes to hours, it actually tightens up your muscles over the long term.  Which then results in you wanting to stretch more, and the "addiction" begins.