I gave up reading after the first few replies. I think people are being really harsh.
Your kids sound like they were being kids. It's normal for them to want to explore and touch stuff. Obviously your job to make sure they don't.
It can be hard enough sorting one child out while paying for something. Let go of their hand to get your wallet/purse out and they're off. No matter how much you've tried to teach them not to. No child does what they should all of the time. People will always judge you for those times they don't do as you need them to.
My dd is absolutely full of energy, all day long, no matter what we do in a day. And she is naturally loud. We're constantly telling her to calm down and talk normally. But that is her normal. And although I don't want her annoying people all the time, I also don't think it's fair to her to be told that all the time and not be herself either.
The only thing I can see wrong with what you did is letting your child play with a toy in the shop, if you weren't buying it. Your posts don't say either way. If you were buying it, not wrong.
As you were using reins, you should have hold of these for the times you need to look away.
Well done to you though. Managing one as a team can be challenging at times, hats off to you to having to manage 2 all of the time. I'm sure you're doing a great job. Try not to let the cranky ones get to you.