If we misrepresent or misinterprete a thing, then we have explain from what context we understood certain things and they of course, apologize. Rules like these are unsaid and they apply to all.
Vishal condemned Radha Ravi's comments against Nayantara and said that he should be ashamed to put Radha in his name.
He meant he shouldn't be causing shame to a legend's name. Also used the name to say that his name ironically means a woman's name.
But Radha Ravi as he is being blasted from all sides, he chose Vishal as his target. He said, "Vishal doesn't know anything and he thought my name is Radha Ravi for some other reason. My name is Radha because of my father but he understood differently!"
As he can take on Vishal saying that they have long going feud, he chose to comment on him when entire Tamil Industry is slamming him.