I suppose I should clarify my stance a little bit. I think that we should have the ability to carry in a lot of places, but there are some places where the potential for carry by almost anyone introduces a lot of risk for minimal gain. The prime example of this would be a sporting event, or someplace like the federal capital. As much as we all might disagree politically, we are peaceful, rational, reasonable people who do not use violence to further our political aims. We are also an extreme minority of people, and to provide effective security for our representatives and leaders, the security organizations do have a legitimate reason to seek a monopoly on force in those areas. It is functionally impossible to allow concealed carry into someplace like Congress and be able to maintain a defensible posture on one person one would have to have a literal shepherd on every visitor in every person in the building at all times. That is impossible.
I would even say this applies to many of the places on the national mall. There isn't really a threat there, and the police are Omni present. I would imagine that that's where the vast majority of the tourists in DC go.
Now, for DC residents, that's a different story. They should have the same rights afforded to them is every other American. They should be allowed to carry concealed weapons in their homes, as they go about their business, and as they recreate. They should also be afforded full representation in Congress, but that's a political issue that one party has fiercely resisted for decades because it advantages them to have Americans with fewer rights then the rest of us, so I won't discuss it any further.
I do think it is legitimate for anyone carrying a weapon in DC to understand that there are some very real reasons and restrictions on what is possible versus plausible and that their carriage should be adjusted to meet those realities.