After reading up on the research on this, we never let our kids have regular screen time as toddlers. Sure, they got it here and there and it didn't damage them forever seeing an occasional movie when we're to dinner at a friend's house, nor do I judge using it as an occasional emergency tool like the PP mentioned, but I would never let it be a regular thing. Screens don't facilitate learning human interaction, they retard it. Kids that age need to be using their entire bodies to interact with a diverse environment with all their senses. They need to be interacting with other humans. This is how we are evolved to learn at that age. Screens are new and they change young brains. Also, it's not unusual for 2 year old to be able to figure out how to work things on a smart phone - go to a pediatric urgent care waiting room or the gate of a delayed flight - lots of bitty kids can entertain themselves this way. The devices are made to be easy. I've seen a lot of parents seem delighted to see this behavior, but it's not exceptional.
I have no problem being "cruel" to a child if it means limiting or forbidding something they like that is harmful to them. My son would have eaten only pasta and candy if we'd let him have his choice.