I actually like teaching schoolkids how to plant. Maybe these kids have a tiny patch of land at home or room for a pot to grow herbs or a tomato plant in. Sure, for Michelle it was a photo op, but teaching kids to grow veggies is a good thing.
If they are going to grow container tomatoes, they need to be taught plant physiology and how to deal with problems like staking or blossom end rot. Container plants really do best if they are miniatures or dwarf varieties bred for pots, to begin with. Not all vegetable plants will do well in a container.
Because container gardening is one of my hobbies, I end up talking about it to people all the time, including all the mistakes I have made, all the problems that can be encountered and how to deal with them.
Most urban dirt is dead, rocky, full of road run off (oil/road salt) and unsuited to gardening. Even suburban lawns can take three years to turn into suitable gardens. It takes that long to get the grass roots out. But, I have read about urban gardens that have been done correctly. A lot of them seem to be raised beds, to get around the dead dirt problem.
I do agree that it is good to try and inspire kids to garden or even just to grow something in a pot. Actually, I think it is good for everyone. But, most people are going to encounter failure and then just give up, if they think it is simply about setting out plants and then suddenly having food.