shopper had ~4yo and ~9yo children delivering groceries to my second floor apartment

I just had a shopper use her kids to deliver my order. One of them was so small she couldn't carry the grocery bag up the stairs- I took the bag from her midway so she wouldn't fall(I always help bring the bags up especially when I order juice etc.). Mom was there and helping, but the kids were clearly not having a fun time and being expected to haul grocery bags to a stranger's door.

Am I being weird about this? I was super uncomfortable but I might be being overly judgmental. I don't want to disrupt a family's income but this is straight up child labor, right?

Please tell me to mind my business if I'm being a Karen about this!