I agree that Ni creatives can come across as manipulative and controlling.

IME, Fe/Ni sees people as processes. Unlike FiNe, which cuts to the unchanging essence of who people are, FeNi implies an awareness of where people are coming from and where they're going (emotionally/psychologically). I'm guessing TeNi is similar, but deals with (and "manipulates") more external elements of processes (not emotions) -- this could be why EIEs are more likely to be called manipulative and LIEs are more likely to be called controlling, although of course EIEs can be called controlling and LIEs can be called manipulative.

This differs from Ni leading in that EIEs and LIEs, with Je as the leading function are primarily focused on the "object" (or, in this case, people), even if they perceive that object as existing in a state of permanent transience (related to Ni). So Ni creatives are more likely to act on their their awareness of people as processes, leading to the alleged manipulation.

Ni creative "manipulation" would also be very different from Se ego "manipulation." Se + Fi/Ti is static and will tend towards a more discrete outlook, so their "manipulation" would be directed towards a very specific, even mechanical outcome, like in a game of chess. By contrast, EIE (or, presumably, LIE) manipulation would be a little vaguer, like pushing people in the desired direction without necessarily having a specific idea of what they want and how they're going to get it.

PS. I didn't mean to make Ni/Se types sound evil.