I swear ex wives be complaining about the dumbest shit

My husband's ex wife has a son who is 18 with autism. I have a 16 year old. There son is a little delayed. Months ago we were on Disney plus and I put on Hamilton. Now my sons name is Burriece. But we call him Burr. So my step son started calling my son Burr, Sir. If you haven't seen Hamilton and don't get the reference just go on YouTube and look up Hamilton- Burr, Sir and listen to the song. Only n really need to here 10 seconds of it. So that's what my step son calls my son. She was picking him upset today and he told my son, "Call you later Burr, Sir". And she asked why is her son calling my son Sir. When he's older. I explained the silly story but she got mad and smacked him on the head and told him to stop that and my son is a " little " boy not a man and how his mother (aka me) is barely a ma'am so he's no where near a sir. It's not that damn deep and she's yelling at him making him cry! I'm not wrong right?

The thing about how is she knows me and my son do nothing but treat both of them with respect so she has no real issues to be upset about so she makes problems out of nothing. Her own mom actually likes me and knows how her daughter is.

Edit: The guys! She's so much to handle and it's sad because I thought it was cute and a great way my son and step son bonded.

Edit: @Briabella, no she just enjoys starting stuff. She is a very abusive person but since our state tends to favor women/mothers my husband was never able to get full custody. I already told her why he was calling him Sir. And she still hit him.