its the difference between knowing the taste of your audience and not knowing what you're delivering (Fe polr), vs knowing what you're delivering vs not knowing how it will be recieved (Fi polr). Fi polr knows the tone they're taking but tends to mistake the effect it will have because they misunderstand the values of the listener; whereas Fe polr tends to understand the position of the listener but misunderstands their own delivery

they both can inadvertently be offensive, but Fi polr tends to make jokes that offend people because they assume no one would find them offensive, whereas Fe polr understands what makes a thing offensive they just have little to no control or awareness over the mode of expression used to deliver the thing, which in turn can create offense or misunderstanding. in other words, Fi polr meant to say the thing in the way they said it, they just didn't realize it was offensive. Fe knows what makes a thing offensive but didnt realize the way they were saying what they were saying could also be offensive or misunderstood. Fi polr struggles with values, Fe struggles with expression