If you go back and reread the posts, you will see that he didn't "forget" that his pistol was now visible, he knowingly carried open. While I do agree that it shouldn't be a problem, in a city setting like that, it's really not going to gain any support for gun rights!
And, I also agree, as I've posted earlier in this thread, that the OP was in Condition White, which NOBODY should be while carrying (or even when unarmed, although carrying a handgun definately requires RESPONSIBILITY), concealed or open. That fact was proven when he was surrounded by police, pushed against the magazine shelf and disarmed. He shouldn't be angry at the police for doing that, he should thank them for it. Maybe now he'll be at least a little more aware of his surroundings! Just think what would have happened if he was disarmed by a criminal that he was completely oblivious of. Getting himself injured or killed is one thing, but now a criminal would have a weapon that could be turned on innocent bystanders.
It's called responsibility. But, instead of taking responsibility of being taken by total surprise and disarmed, he wants to blame someone else.