Nirvana Fallacy

The nirvana fallacy is a type of logical fallacy comparing an argument, position, or object to a fantastical, idyllic, or unrealistic alternative in order to assert that the original position or object is false or inferior.

With this fallacy, the speaker is asserting that because the position is "inferior" to this fantasy, it is somehow invalid.

This is often called the "Perfect World" fallacy, in which a solution that does not result in a perfect world is pointless.

An example of this fallacy would be asserting that because driving laws do not prevent people from driving improperly, that they should not exist.