B757 FLC DENIED CTLRS VECTOR TO AVOID WX.

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WE WERE DEVIATING W OF COURSE PARALLELING A LINE OF STORMS ON A HDG OF 335 DEGS MAGNETIC. ZJX TWICE TOLD US TO TURN TO A HDG OF 345 DEGS AND PROCEED DIRECT TO DUBLIN WHEN ABLE. THIS NEW HDG WOULD HAVE TAKEN US TOO CLOSE TO THE WX; AND WE RESPONDED; 'UNABLE DUE TO WX' BOTH TIMES. ATC THEN RESPONDED;' IT IS NOT A SUBJECT FOR DEBATE; TURN TO A HDG OF 345 DEGS IMMEDIATELY.' AGAIN WE RESPONDED; 'UNABLE DUE TO WX.' ATC THEN STATED; 'THERE IS NO WX BTWN YOU AND DUBLIN; I UNDERSTAND YOU ARE EXERCISING YOUR EMER AUTH; THANK YOU!' AND GAVE US A FREQ CHANGE. THESE FINAL COMMENTS WERE BOTH CONFRONTATIONAL AND SARCASTIC. AT NO TIME DID WE DECLARE AN EMER NOR REQUEST SPECIAL HANDLING BEYOND WHAT I NORMALLY EXPECT WHEN DEVIATING BECAUSE OF WX. IT WOULD HELP TO HAVE ATC'S CONSTRAINTS VERBALIZED (IE; CONFLICTING TFC; YOU'RE LEAVING MY SECTOR; ETC). THERE IS NO WAY FOR ATC TO HAVE A TRUE PICTURE OF THE ACTUAL WX CONDITIONS (IE; OVERHANGS; ROTATOR CLOUDS; ETC) EVEN IF HE'S LOOKING AT A WX RADAR PICTURE. ALL PLTS HAVE DIFFERENT WAYS OF EVALUATING WX AND THEIR OWN CRITERIA WITH REGARDS TO DEVS. ON OUR PART; I SUPPOSE WE COULD HAVE INQUIRED OF THE REASON FOR THE HDG CHANGE.