Below are several verses from the Dattātreya Yoga Shastra, considered to be the first text describing Hatha Yoga in about the 12 century CE. False holy men were apparently a problem then, too. Always have been, always will be.
”It is a well known fact that men who wear religious garb
but undertake no religious practices deceive people
by talking of yoga for purposes of lust and gluttony.
Crafty men try various deceits; declaring ‘we are yogins’
they are fools, intent on nothing but their own satisfaction.
Gradually coming to realize that men like that
do not practice yoga, but attain their ends through words alone,
one should shun those who wear religious garb.
These people are always obstacles to your yoga practice.
One should take pains to shun them.”
Dattātreya Yoga Shastra, 3.1.2, v47-50



