He apologized to the members who had planned on attending functions. You think that is outrageous? I think its good manners.
He also said "But it's fitting and proper that we should do this. Because NRA members are, above all, Americans. That means that whatever our differences, we are respectful of one another and we stand united, especially in adversity.". To stand united with fellow Americans in grief.
And he was correct when he said, "Still they say don't come here. I guess what saddens me the most is how that suggests complicity. It implies that you and I and 80 million honest gun owners are somehow to blame, that we don't care. We don't care as much as they do, or that we don't deserve to be as shocked and horrified as every other soul in America mourning for the people of Littleton". The NRA WAS blamed for not cancelling the member meeting, despite the fact that the only way they could have legally cancelled it was to notify 4 million members in 24 hours. They did not have the functions that they could cancel.
You make it sound as though the NRA decided to come because of Columbine.
He did speak to the grief, and to the discourse that was sure to follow. "To help shoulder the grief and share our sorrow and to offer our respectful, reassured voice to the national discourse that has erupted around this tragedy.".
No, he didn't say the kids shouldn't have had those guns. Perhaps because it was already illegal for underage kids to have firearms? He stayed away from blaming anyone for what happened.
There are people to blame for the Columbine shootings. The NRA is not. Blame the people who saw the website, the journals, and heard the threats and did nothing. Blame the psychologists who let them off. But the NRA did not cause that, nor were they trying to cause problems after the event. The NRA had an annual members meeting in Denver, and that was all they did.