Regardless of where the discussion began, it shifted to an animal multiplication factor represented by N, where the value of N determines the level of cruelty. While I ultimately agree that comment did not consider a lot of open questions, possibly due to being posted in haste, it was good enough to establish a focal point and it became the place where the discussion continued from.

An animal is an animal is an animal. While it is true that there is fluidity in language, and that one could define animal as only a creature kept by humans for the purpose of extracting meat, there was no push back on the use of the more common, broader definition that would be reflected in the dictionary.

Plants have not been considered animals. There has been a clear division between the plants harvested and the animals affected by it throughout the discussion. Whether or not their suffering should be included is and interesting side topic, but immaterial to this one. There is no value in flailing around trying to find new metrics. We picked one. It was certainly not perfect – far from it – but it was good enough. Perfect need not be the enemy of good.

While the philosophers have a point, we are only seeking something to form a belief. Beliefs need not be true. But they do need to be formed, and it seems we don't have enough information to form any kind of beliefs here?

I think you're mixing up the categories now. The animal originally in question for the factor was the slaughter animal, and the N factor applied only to those.

Otherwise, the discussion falls apart because a human is an animal is an animal. But no one is slaughtering humans with such an enthusiasm as cows or chickens. Equating all animals is a fringe belief not supported by the population at large, and one I don't feel like spending time to discuss, especially as it's not required for this discussion to have been valid.