Corporate tax (at least in the US, and I assume in most other places) is calculated on income, i.e. revenue minus expenses. The original commenter was asserting that halving the company's tax rate, and nothing else, was responsible for a doubling of profits. My point was simply that it should be obvious that this is nonsense. Cutting the tax rate can't double the company's profit unless the company was already paying half of its income as tax.

It's irrelevant that expenses are a large fraction of revenue, because expenses are already excluded from taxation.