Why do people mistake Frankenstein for the monster?

This is so stupid, why can't people get this right? "Frankenstein" is not the monster, it's the mad scientist who creates it.

In the novel, the monster is identified only via words such as "creature", "monster", "fiend", "wretch", "vile insect", "daemon", "being", and "it". Speaking to Victor Frankenstein, the monster refers to himself as "the Adam of your labors", and elsewhere as someone who "would have" been "your Adam", but is instead "your fallen angel." -- Wikipedia