I should point out that pellet guns do not have a 'Day-Glo Safety Orange/Red' tip.
As they do eject actually harmful projectiles; they look much like other guns until you get close to them. Reasonable parenting would have included making sure the child understood that under no circumstances do you point that at people.
That doesn't make this less of a tragedy, but it does provide some context to the situation. Cops are, sadly, trained out of necessity not to try to discern when on the receiving end of any gun barrel. While it's difficult to expect a child to know not to point weapons at police; doing so is in fact dangerous.
You can't really trust the orange tip anyway, since criminals have been known to paint that on real guns to trick cops, with mixed success.
Regardless, from a police officer's perspective, you only have half a second to tell whether an object that someone is getting out of their pocket is a gun or something less harmful, like a cell phone. So it's understandable why they chose to shoot in this situation.
Of course, if it were harder for the general public to get guns, then police wouldn't be put in these situations where they have to make life-and-death decisions in under a second, but we have to live with the consequences of which rights we chose to value.
if it were harder for the general public to get guns
Is there anywhere harder to get a gun? Even pellet guns are illegal in NYC. You can be legal in one state, passing through to another state where you're legal, and NY can take your ass to jail for a gun in the trunk.
Laws aren't, by themselves, an effective way to keep dangerous guns out of the hands of criminals, because it is really easy to (illegally) import guns from a place with lax gun laws into a place with strict gun laws. There's also a problem with existing gun laws encountering enforcement problems from law enforcement agencies who refuse to enforce them or who don't care enough about it.
On top of that, there is a cultural problem where guns are associated with masculinity and being "cool". That leads to way more people acquiring them than there really should be, and many of those people really shouldn't be having them. That's not something the law can fix.