A large proportion of ENFPs I have seen on Typology Central and Youtube seem to be very fascinated with ISTPs
A lot of mistyped ExFJs maybe? I really suspect a chunk of female "ENFPs" online are ESFJs (tertiary Ne, same "Get Things Going" interaction style, may think that their adherence to certain trendy ideals makes them the "free spirit & progressive" stereotype of the ENFP).
INTJs and INFPs are in Benefit/Request relations where INTJ is Benefactor to INFP. These are asymmetric relations where INFP will be prone to putting INTJs on a pedestal:
Benefit Relations
I see some INFPs do this, but I've seen some INTJs do this too with their INFP partner/love interest (in those frequently occurring threads in INFP forums where the INTJ wants to know what's up with an elusive INFP they're trying to nab).
TypeLogic has INFP listed as the INTJ's "advisor", which the site says is "having an area of insight that the other lacks". That seems to flip the socionic roles a bit or even it out at least. While the site doesn't go into great detail about this theory, I personally find its brief descriptions of type relations a lot more accurate to my experiences than socionics.
My experience is always somewhat opposite (to the INTJ/INFP socionics relation); I'm never quite as interested as they are, or at least to the degree that they claim they are/were interested, so that it seems I'm more likely to be put on the pedestal.
A lot of it may have to do with non type related stuff though (ie. physical appearance), and I still think those are huge enough factors to outweigh type theories of what type is the ideal romantic match (otherwise we INFPs might have a chance with
no one 
).
For instance, my younger INTJ cousin was semi-obsessed with me when he was a kid (I have some stories about that; both creepy & a bit amusing). However, I was never as interested in him as my ESFP sister, who LOVES kids & would cart him around everywhere to do fun stuff. I'm pretty sure his crush on me was partly a masochistic unrequited fascination, because he was just another annoying little kid to me, & I mostly ignored him. This disinterested attitude no doubt played some role, just as it seems to in those INFP forum threads made by INTJs.