False dilemma

A false dilemma is an argument "in which two alternative points of view are held to be the only options" (W) when in fact other options are available.

This fallacy comes in several flavors:

• "You're either with me, or you're against me." (Or, more mildly, "You're either with us, or you aren't.")
• "You're either part of the solution, or you're part of the problem."
• All-or-nothing thinking (a recognized form of cognitive distortion in cognitive therapy)

This is related to the rhetorical technique of choice between extremes, where any other options may have actually been made unavailable, rather than simply being ignored or dismissed by the arguer.

Reference

• Wikipedia