To me, the intention end-goal is the definer of "manipulation":
Am I behaving the way I am in order to create a safer/happier world just for myself, or to take advantage of someone else for my benefit, at their expense? (this is manipulation: Self-centered tailoring of the self to appease others)
Or am I doing things not just for my benefit but for the maturation and actualization of other people? (This is consideration: Tailoring of the self in order to benefit others and the community as a whole, including oneself.)
Inexperienced T's seem to get hung up on an impersonalized view of truth... as if truth is something completely outside human interaction/nature and thus reducing people to objects that should operate the same as rocks or trees.
People operate under a different system than "objects." You have to learn the system and see how people best operate, and then, if your goal is to better people, learn how to say truth in ways that actually create positive result.
What NT's seem to label as truth early as children (and have to work to mature out of) seems simplistic and sloppy to me. Others are forced to pay the expense of the T speaking the "truth." Let the tables be turned for once, and have the young T be faced with constant blunt criticism under the guise of "truth-telling"... and be amazed at how angry they'll eventually get, and how negatively it will impact their maturation as people.