I didn't want to put this in the Beta section because I think it's a topic that deserves more visibility and discussion.
Anyway, it's taken me a long time to finally conclude this, but EIE-Fe tend to vary more from one another and are easily mistaken for other types (SLE-Ti, ILE, SLI, and even their LSI-Se duals come to mind, but especially SLE), whereas like 80% of EIE-Ni are easily identifiable as EIE-Ni (I knew one who was an asshole and could easily be confused for his conflictor in one photo, he looked like Jeff Daniels, but I noticed he was an EIE-Ni as soon as I meet him).
EIE-Fe keep themselves at a distance more and they're less emotionally expressive, less sentimental, less biased, as adults they seem to not want to cause a bad emotional atmosphere. They're far more skeptical of stereotypes, and well, everything. They're greater skepticism probably causes them to participate in groups, new activities, competitions, etc., less so they get a lot less visibility. But even when taking into account the Fe subtypes lower visibility, they're still less common.