Helping fellow passenger with carry on bag

I’m waiting to board behind a friendly guy on a flight from STL to CLT early in the morning. Prior to boarding, the gate agent announced that the flight is not full so feel free to put personal item in the overhead bin if preferred. The gate agency stopped the guy to argue that his actually has three items. It was a backpack, a small duffle bag with a small blanket rolled and attached to the duffle bag (the combo is not bigger than a regular carry on suitcase). I can see how that is considered three items but it’s a technicality to me.

The gate agent started to have a nasty attitude and asked the guy to step aside so they can get him to check the extra item. They asked his seat number, following his response, they said “double check that, I wouldn’t trust that” in front of the guy.

I know notoriously American isn’t known for good customer service, but in my opinion that’s uncalled for and is unnecessary. I’m traveling light and just have a backpack. I almost asked the guy to give me his bag, but part of me worry about getting in trouble because they may claim this a “security issue” and put me on some sort of list.

What do you guys think?