Oh come on, can we not give the OP a break? Kids do daft things and it's upsetting when they get hurt. And the fact is, most people don't buy individual pots and decant them, or they'd buy a big pot and save money. I think a lot of us react unreasonably at times when our kids are in pain, and if it was an especially nasty cut all she is doing is trying to stop other people's kids getting one. That's hardly a nasty or malicious thing to do.
OP, the reality is that when people break plastic, it will leave a sharp edge, same as when you open a tin (though thankfully nowhere near as severe). As a matter of fact, the foil top can cut your tongue if you lick it - I did that as a teenager, to get the thick bit of yoghurt there. But it's very fine metal, so it would.
We can't protect our kids from everything unless we spend more money. The truth is, these companies sell snappable pots because they are cheaper to manufacture and distribute than the individual ones. But if you really want to avoid the issue, those Suckies fruit yogurts that come in pouches could be the solution, maybe? More expensive, but no chance of a toddler injury.
TBH, I think toddler's suffering minor injuries educates them about the world we all live in, and how to manage risk. Horrible to watch as a parent or grandparent, but probably quite good for them in terms of learning to stay out of harm's way.