Vinegar is an acid. You said if it's safe to drink it's safe to rinse your lenses with. I'm pretty sure your cornea will be damaged if you rinse your lense with vinegar and stick it in your eye. So your point that if it's safe to drink it's safe to rinse a contact lense with is patently false.

More to the point, your stomach has acid that can kill microorganisms in tap water. Your eye has no such defense.