I have absolutely no reason whatsoever to doubt a single word d a stated. In fact, d a’s description fits in very well with Rabbi Miller’s teachings and gadlus.
You also have provided no corroboration of your stated or implied description of Rabbis Cohen, Goren, and Sacks opposing eating meat because they held it was wrong to eat meat for a reason other than health or enjoyment. (d a’s description stated Rabbi Miller only opposed the practice of vegetarianism when accompanied with the belief that eating meat is wrong.)
Additionally both Rabbis Goren and Sacks were never considered to be amongst the Gedolim and in fact have taken controversial stances condemned by the Gedolim. (Rabbi Goren was vehemently opposed by the Gedolim for his controversial positions on mamzeirim amongst other things, and Rabbi Sacks for his endorsement of pure relativism between religions, and that Judaism is not the sole true religion i.e. “No one creed has a monopoly on spiritual truth.”)