Yeah, killing 10 people and maiming dozens of others is no big deal. You betcha. Just an accident.
Are you saying it couldn't be an accident? Or are you saying that even if it was an accident, the driver should be punished? Maybe he should be executed? Maybe anybody involved in such a terrible accident should be executed, as well?
It is a big deal. It is also an accident. What purpose is punishment of this guy supposed to serve? To keep other people from having accidents?