I would recommend checking out Professor Volokh's series of YouTube videos on the First Amendment. [1]
It’s the same Doublethink that defines income taxes as exclusive of payroll taxes by naming a subset of income taxes as income tax.
And as for payroll taxes, they are still taxes, but they are not applied on all income. For example, they do not apply to capital gains, or to income above ~$140k. Also, social security is (at least in theory) a forced savings plan, and people who pay into it more over their career then receive more out when they retire.
Income taxes, on the other hand, are not capped at a certain level, and you never get money back later based on how much income tax you paid in the past.
There are times where it is silly to refer to them in the aggregate, but it is not "Doublethink" to talk about them separately. They are different in important respects.
To show why this is a logical fallacy.
The US definition of income taxes also excludes gifts received even though that’s also “income.” As such by your definition they aren’t income taxes. Of course you could just define gifts as not income and things are ok, except if you continue to define income taxes as taxes based on a specific system then the definition is only applicable to that system at a specific point in time.
For example, is money received by tax free investments income? That’s now undecided until you determine the specific source, time period, and country involved. And as soon as you have statements that are both true and false you have a problem.
Even if you want to stick with US definitions, the states and federal government have different rules. As such the exact same transaction can be both income and not income. Which is about the clearest example of Doublethink I can think of.
PS: Instead, if you say for purposes of X it’s defined as Y then you don’t have this issue. But, then it’s very clear that specific things are exceptions. (To be clear I kept adding to this comment.)
Because denying something happened doesn’t physically hurt anyone. Mostly just dumb.
Asking for it to happen again means one is an evil monster that needs to be stopped.
Picking arbitrary facts as somehow political issues is very dangerous waters. I honestly have less problems with someone saying a Holocaust was a good idea than I do when people say they aren’t happening.