AITAH for phone use in locker room

My wife (28F) and I (29F) take our son (2M) to the pool every Saturday morning for swim class. After class, I change first and my wife showers our son and then I change him while she gets changed. I changed my son and gave him a snack. He was pretty wiggly and wanting to run all over the locker room. I can’t take him to the lobby or he will cry for mom. So I took him into one of the private changing stalls and closed the curtain half way. The view to the locker room from the stalls is only the sinks in the bathroom. There were plenty of changing stalls available. I turned a YouTube kids thing on the lowest volume and set it on his lap on the chair while I packed the bag. My wife was changing in the main locker room. A lady came over from the sink and told me to put my phone away. I asked if she was an employee. She said no, but I shouldn’t have my phone out in the locker room as there is a sign. I told her we came to a private area so as not to make folks uncomfortable and that I was simply distracting my kiddo while I packed my bags so he didn’t make anyone changing in the locker room uncomfortable by running up to them. I then closed the curtain the rest of the way. She came back about 3 minutes later and opened the curtain and said she was going to call an employee if I don’t put my phone away. I said to leave me alone and just closed the curtain. My wife finished up changing and we left about 5 minutes later and spoke to the employees at the front desk who said the signs are more for not taking a video or voice recording or call, and appreciated that we went to a private area before getting a phone out. I understand peoples concerns in public changing areas but I genuinely don’t think I was the asshole here.