No. Their argument is based on applying their subjective beliefs that I don’t share to my actions and as such by definition not sound.
Do you believe that racism or sexism is wrong? Do you think a racist or sexist person would share your belief? Are you not, then, applying your subjective beliefs that they don’t share to their actions?
We judge others based on our moral standards, not theirs. To someone who sees the killing of an animal as a great sin, your actions might therefore seem wrong.
Or maybe a general opposition to violence, or a concern for the ecological impact of domestic animals, or a fear that it could cause the next pandemic.
This is a weak argument. Based on your abortion example, I’m guessing you are from the US or southern Europe. So, you might know of the Confederate States of America and/or Fascist Iberia / Italy. In those places, were there not people who did not consciously support slavery / fascism, but went along with it because they ‘did not have an ideology’? How would you judge them?
Further, on your not having an ideology, do you support the eating of humans? Monkeys? Cats? Dogs? Which animals are haram to you, and which ones are halal?