That is not some universal law. It is a convention that assumes a certain scenario, namely where the government has been receiving a certain amount of tax reven

That is not some universal law. It is a convention that assumes a certain scenario, namely where the government has been receiving a certain amount of tax revenue which they will now lose by giving a break. In a scenario where a crazy new tax was passed that was never enforced, then noticed a few years later and abolished because enforcing it would blow up an entire local industry, it is a stretch to categorizing it as "spending". That'd be like writing a note you're owed $1B, tucking it in a drawer, and then when it's ripped up a few years later saying you just "spent" a billion dollars. The city never had the tax revenue to begin with.