Again, with the relevant mishnah on the previous daf: Buying from shops that are adorned for the non-Jewish pagan holiday was prohibited. Especially when the decorations were scented (eg - roses). Which leads to defining "benefit" - as deriving benefit is what is prohibited, while causing benefit is acceptable, or at least it can be. The concern isn't that of funding idolatry, but the Jew's benefit from idolatry. Plus, those who wore a wreath of roses - an idolatrous practice - received a reduced tax rate, but if you declined, then the extra tax would cover more idolatrous practice. Also, a discussion about not cutting the tendons of a sacred animal because it looks like you're inflicting a blemish on the animal -- but it doesn't just appear like you are; you really are! That prohibition against harming the animal is even - and specifically - in the case of an animal that can't be offered to begin with.