I would think "fake", as in someone pulling a prank, trying to make fun of a particular group, knowingly deceiving, would be quite easy to spot for someone with heightened empathy and ability to read others' cues. Feigning empathy around INFJs would be sort of like pretending to be fluent in French with a native speaker. The only difference is, unlike the French, we wouldn't really care.
I might be another kind of fake, mis-identified. You could certainly give me feedback, suggestions, point me to a nice forum. I like to meet new people =). I did not set out to find a glamorous MB identity and confess I don't think it's super special other than that it gave me an "aha" about myself.
In particular, I have some conflict about thinking vs. feeling, and actually aspire toward I guess an ethical INTJ? I think society run too much by feelings is dangerous. But I don't know if this reflection is more INFJ or INTJ? I discussed the rise of contemporary populism with an INTJ the other night actually, and his response was to not worry because I'm not a vulnerable member of society (economically, racially, in terms of citizenship). I felt on an analytical level we could both reach the same conclusions, based on our values of freedom, civil society, etc., but our emotional reactions were different. So maybe the feeling part isn't needed so much?