Feeler stereotypes likely originated with dominant thinkers (ENTJ, ESTJ, INTP, ISTP), because the feeling function is in the inferior. Our inferior function is often somewhat inaccessible or uncontrollable, on a conscious level, and encounters with it, in others, are typically demonized. Dominant thinkers are uncomfortable with basing decisions on that which matters most to feelers, personal values and feelings about things. Similarly, thinker stereotypes almost assuredly derived from dominant feeler (INFP, ISFP, ENFJ, ESFJ) types, because they base decisions on personal standards, and are loathe to do otherwise. They may think it cold, callous, etc. to do such a thing, because it's directly opposed to what they're naturally inclined to do.
However, I wouldn't say feelers were truly more emotional. A great many ENTJ profiles, for example, mention anger problems and some even suggest anger management, suggesting this is a very common trait of the type. Furthermore, I've witnessed an INTP deteriorate into the immature SFJ mode, when they couldn't get Ti's needs met, in a debate, and interacted with an ENTP, who actually seemed to be slipping into clinical depression, because they were currently in an environment where their ideas were constantly being attacked or instantly dismissed. Yes, even the stone cold NT's can be emotional creatures. All it takes is the right triggers. After all, we're all human. Emotions have little, if anything to do with type. Perhaps, at most, type may decide, to some extent, how we deal with them or what triggers them.