This back and forth actually shows part of what's difficult with applying NVC: when a statement is made, another hidden meaning may be inferred by other participants in the conversation, even if such meaning was not intended or even considered by the speaker. It's worse given that some people specifically do say the same types of things with ulterior motives, so it isn't entirely unreasonable for other people to come to the conclusion that you are doing so as well.
This would work better if both parties practiced NVC, as they may reply with what your comment made them feel and that would help clarify the confusion. But it's going to be hard to find that type of situation given that NVC is not quite that widespread, so the NVC happening on only one side of the conversation truly make it difficult.
So we have to either be very careful with our wording and be aware of all possible misinterpretations, to make sure our wording only says what we want it to say, and/or we have to keep clarifying ourselves until our true meaning is clear and confirm with others what they've understood, which can be awkward. No wonder NVC is hard.
This would work better if both parties practiced NVC, as they may reply with what your comment made them feel and that would help clarify the confusion. But it's going to be hard to find that type of situation given that NVC is not quite that widespread, so the NVC happening on only one side of the conversation truly make it difficult.
So we have to either be very careful with our wording and be aware of all possible misinterpretations, to make sure our wording only says what we want it to say, and/or we have to keep clarifying ourselves until our true meaning is clear and confirm with others what they've understood, which can be awkward. No wonder NVC is hard.