Speciesism = destruction by definition
The “common denominator” is often used to derogate animality:
Like “animals and humans both experience emotions/sensations like pain, joy, hunger, affection” … yet nonhumans are supposedly driven by instinct the same people say at the same time …
The common denominator only is that: a common denominator. It doesn’t explain animality in any sense autonomous from human domination.
Putting ourselves as “humans” in hierarchies over nonhuman animality mostly stays in place with people citing the classic common denominators, where nonhumanity is attributed with any similarities or resemblances we think fit for the nonhuman animal realm.
As long as people explain nonhumanity in terms of biologistic or any other reductive parameters, common denominators aren’t really a step to break up the theoretical disenfranchisement that always makes up the basis for human societies to ‘destroy by definition’.
The common denominator gains its sense when you accept the compared one in their own autonomous and thus inviolable rights.