Here are some simple thoughts that embody the abolitionist approach and philosophy. They may be useful to you in your own thinking about things as well as in your discussion with others:
1. Speciesism is morally objectionable because, like racism, sexism, and heterosexism, it links personhood with an irrelevant criterion.
Explanation: We do not object to speciesism in a vacuum. We reject it because it is like other forms of discrimination. What all forms of discrimination share in common is the use of an irrelevant criterion to exclude people from full membership in the moral community. Racists devalue those of different races based solely on skin color; sexists devalue women solely because of sex and gender; heterosexists deny full membership in the moral community to gays, lesbians, transgenders, etc. simply on the basis of sexual orientation. Speciesists deny full membership in the moral community based solely on species.
All of these forms of discrimination are morally unjustifiable. We reject speciesism because it is indistinguishable from these other forms of discrimination.
(Please note: Although Peter Singer ostensibly rejects speciesism, he maintains that because nonhumans do not have the same sort of minds as do humans, they do not have an interest in continuing to live and we do not harm them if we use and kill them “humanely.” I find this a form of speciesism. Click here.)