Consistency is what we build into FAIs, not what we require of ourselves before changing what we would do. If animal suffering is bad enough that we should be an animal rights campaigner, but we nevertheless unethically choose to not become a campaigner, that does not make the decision to eat exactly as much meat as always suddenly an ethical decision.

Is it futile to eat a side of asparagus with your steak rather than a side of calamari? Not at all, we have still saved expected squid equivalent to one side of calamari. Would it be better to not have the steak? Sure, maybe, but the squid doesn't actually care about our inconsistency.

I recently (gradually over the last half-year or so) became a fair-weather vegetarian. I ate pepperoni pizza today, and it would have been more than negligible cost to do otherwise. But the last time I bought groceries I did not purchase any meat. I find that I can forgo something like 90% of the meat I used to eat with positive marginal happiness, since most of the time it's fairly trivial to switch to a non-meat idea instead and I still get more pleasure from the decision to switch than unpleasantness from the switching costs.