Not sure how to feel. (I'm mixed black/white). I got attacked for commenting (more in post). Was the person wrong for attacking me? would you be offended?

Ma
One of my friends is graduating with her masters. She is black. She commented about how her graduation is coming up and used a bunch of hashtags one of them was #blacknuesesrock
So I commented: congrats I'm so proud of you! #MSN #blacknursesdorock
One of her friends attacked me saying...tell me how your white privelaged ass knows about black nurses. 
Now I look mostly white but it's like why assume? I was kindly congratulating her. Would you be offended?