At the end of last week, a paper I wrote (PhD, second year) got a Minor Revision (IEEE Transaction, TAFFC), receiving good comments from all three reviewers involved. Two unknown reviewers plus an admitted psychologist were involved in the review, with the latter sharing very positive feedback and deep interest in the topic. Therefore, I thought it would be useful after the work was published to get in contact with this reviewer to collect more feedback and understand how to extend the work further, with the possible aim of collaborating.
I expressed this desire in written communication with all co-authors without deeply thinking about it. However, the last author (last author, FP, senior, former supervisor) appeared quite disappointed about my email, saying that this behaviour is highly unethical and never should any author try to contact the reviewers after publication. None of the other co-authors took part in the conversation.
I read here and there that it is possible to contact the editor to know the reviewers' identity and to have further conversations about the topic. Therefore, I completely do not understand their position. I was quite shocked at the beginning even though the conversation stopped there. Do you have any input about this situation? I am afraid of speaking with my former supervisor about it in person because I want neither to receive similar treatment again nor to annoy him.
EDIT: I want to thank everyone who spent time answering my request and allowed me to view this experience from a different viewpoint, especially from the one of the reviewers!