False dichotomy
Etymology
Dichotomy comes from the Greek "dikhotomia," a cutting in two — "dikha," in two, plus "temnein," to cut. The fallacy is also called the false dilemma or either/or fallacy. The error is in the cut itself: pretending the world splits cleanly when it does not.
noun phrase · /FAWLS dy-KOT-uh-mee/
Presenting only two options as if they were the only possibilities when others exist.
What it names
Frees you from a forced choice between two extremes when a third path is available.
Example
"You’re either with us or against us" ignores everyone who supports the goal but questions the method — a false dichotomy.
Related idea
A loaded question smuggles in an assumption the same way, but through a question rather than a pair of options.