I believe it is Harram - forbidden to insult the sahaba's named, or any of the wives of Rasullah s.a.w
From Ayatullah Sistani: http://www.shiachat.com/forum/topic/235017990-al-sistanis-on-insulting-the-wives-and-companions/The Question:as-Salamu Alykum wa rahmatu Allah wa barakatuhu,A video clip has been seen several times on social network web sites showing a congregation during the martyrdom of al-Imam al-Jawad (a.s.). This group of people from the area known as al-A'dhamiyyah are shown shouting out insults upon 'Omar, A’isha, and others. Is this type of behavior condemned by the supreme religious authority, especially since it involves the insult of religious figures of our brothers of the Sunni school of thought, and it could potentially fuel unrest amongst the people of Iraq and jeopardize peace?
The Answer:In The Name of Allah, The Beneficent, The MercifulThis type of behavior is condemned, strongly denounced and contrary to the commands of the Imams of the Holy Household of the Prophet (s.a.w.a.) to their followers. Allah is The Guide. Ali a.s is not God, auzubillah. Nor is he divine, auzubillah. He ate, slept, used the toilet, was wounded , died. He is a slave of Allah swt, but one of the most closest servants to Allah swt.
By exalting him to the extent of commiting shirk - what do you mean by this ?