The powers that be in this world could convince most human beings that anything is 'normal'. You talk of cannibalism as if it is inherently worse than eating animals when, on an energetic level, it is no less morally repugnant.
'Our' Masters have convinced 'us' that the extreme holocaust perpetrated against animals every day is 'normal', that woman paying money to have their fetuses forcibly ejected from their body is 'normal', that the mass sacrifice known as 'war' is 'normal' and are now well on their way to convincing an apparent large majority of human beings to walk around wearing masks, whilst living in fear of their fellow human beings.
Most people go whichever way the wind blows. They can clearly be manipulated to believe anything.
To return to your original point; cows, pigs, lambs etc are anthropomorphic enough for "carnivorism" to be considered a form of cannibalism.
And I guarantee you it would take them less than a year to convince the average person that eating humans is normal too.