It is not a question of 'Whether he contributed to decline of another youngster and then another and on and on...'
Question is not whether Anwar Ali was mediocre to begin with, nor that his action was gonna cause him issues down the road (see Klusekara with exactly similar action had a successful few years at the Int'l level) etc.
The biggest question we must be asking is 'Who the heck gave him the right, powers, and supposed knowhow to initiate action change/modifications etc? Why does he have this big chip on his shoulder that allows him to continue to mess with actions/techniques etc. without the requisite experience/certifications and what not!
And even then, for every Anwar Ali/Muddassar/Mansoor Amjad etc. there is a story to celebrate in the form of a Malinga/Thompson/Bumrah on and on the list goes. A huge majority of experts/coaches/specialists only believe in slight modifications over a longer period of time and even then the changes introduced are minor tweaks at best; no wholesale changes are usually suggested just on a whim like he has been doing for the last decade or more!