Yitayningwut: 1) The Mishna is Pirkei Avos explains that the characteristic traits of a person [not his actions]
2)The Torah does not say it is a Mitzvah in general to eat animals; rather the Torah says one is “permitted” to eat animals. Only for specific purposes it is a ‘mitzvah’ to shecht animals. Would you say that killing a child is not a moral issue since the Torah commanded Avrohom Avinu to shecht Yitzchok? A specific Mitzvah Bain Adam L’makom does not contradict the validity of our general feelings of Bain Adam L’chaveiro. Also, the Midrash says that Hashem choose Moshe Rabeinu to lead Klal Yisroel precisely because he showed compassion towards the sheep he shepherded.