It's not debt because unlike (financial) debt, there is no way to not take it or to repay it.

Technical debt in software is unavoidable. Every variable and function and design decision can invariably be rebranded as technical debt soon enough.

The implication of "technical debt" is that there is a perfect state to reach with no debt, but there isn't. It also implies that debt could be avoided but it can't be, it's inherent to development.