I don’t think it is disingenuous at all. You may draw the line at sentience, but you have provided no argument for why this is correct. Why must we consider the harm exactly up to sentience? Why must we only consider conscious pain resulting from harm, and not nociception? It is easy to dismiss people as disingenuous, especially if you don’t really have any arguments for your case.

I don’t see how there can exist any good arguments for where to draw the line, which is why it bothers me when people claim the moral high ground, but cannot offer any arguments on why their behaviour is most morally correct. You can say “reduce suffering of sentient beings”, and most people probably agree, but I think it is completely natural to prioritise yourself, your family and friends and your species above other animals. So how much suffering of yourself is as important as the suffering of a chicken. Probably substantially less. I don’t think you will ever convince anyone of your beliefs by simply denying that their weightings of human-to-animal suffering is wrong and yours is right.