These children are all examples of how awful and terrible school shootings are. Obama says their names our of respect, but also to urge people to remember their names. He wants to get his point across of the importance of gun control laws & protecting the people we care about.
Overall, Obama wants to inspire parents to protect their children. He wants nothing like this to ever happen again. As leader of our country, he has a duty to protect & that is exactly what he wants to do.