Don't you find it kind of ironic that members of Congress are allowed to carry? There actually was a gunfight on the House floor once between two members...........
"Don't you find it kind of ironic that members of Congress are allowed to carry?"
Not a bit, no.
Congress makes the rules that governs Congress. It's right there in the Constitution. Clearly there cannot be any executive branch personnel with guns "guarding" Congress. There's too much history of that sort of thing all over the Western World to make it advisable for Congress to have anything other than direct control over the police who police Congress, and even for Congress to have control over the police power in the city where Congress sits (hence the District of Columbia, answerable not to the police but to Congress).
Think about the White House. Can the President be commanded by the Secret Service not to have his own weapons? No. And if the President SHOOTS a Secret Service Agent, can he be either SHOT by the Secret Service OR arrested by them? Legally, no. In reality, he probably WOULD be subdued by them, on the premise that he had gone insane and needed to protected against himself, but even then, he couldn't be PROSECUTED for murdering the Secret Servicemen unless he were impeached and removed from office. Then, and only then, would he be answerable for his crime.
Once one gets to the top of the government: the White House and Congress, there CANNOT BE a police force with amorphous, abstract authority to restrain the top political leaders by force. Congress sets the rules for Congress, and there cannot be any source of Congressional police rules that can interfere with Congress. If Congress decides that Congressmen can carry, and that the Congressional police are not to know that, well, the Capitol Police serve at the pleasure of Congress. In no sense whatever are they there to POLICE Congress any more than the Secret Service has any right to police the President. The armed guards are there to protect the Congressmen and the President, respectively, against the rest of the world. They do NOT have a law enforcement function over the actual officials themselves. They SERVE the officials, not police them, except and only within the limits that the officials themselves decide to set rules to police themselves. And the officials can change the rules whenever they want to. Congress has full and unlimited constitutional power to set the rules for Congress. It has to. Without that, the Executive branch could effectively control Congress the same way that English rulers and Roman leaders controlled their Parliaments and Senates: by controlling the police who police the Legislature.
Query: should the Secret Service take its orders from the PRESIDENT, or from CONGRESS? It's a vital question. The men with guns around the President, who have the physical power to restrain the President if need be, to whom must they answer? If they answer to the President, then they guard him but they cannot restrain him. If they answer to Congress, then they CAN restrain the President.
So too with the Capital Police. If they answer to Congress, then to the extent that Congress sets the rules, Congressmen do NOT answer to them. If they answer to the President, then Congressmen, as individuals, can be made to answer to the President. Note that the FBI, answerable to the President, CANNOT simply walk onto Capitol Hill and search Congressmen's office. The Executive police power DOES NOT EXTEND to Congress itself, and MUST NOT.
That's why Congressmen can carry: it's THEIR house, they are the masters, there is absolutely nobody in America above them, in their house, and there is no check on their power, in their house. The police answer to them, but they do NOT answer to the police. If they have decided that they can carry weapons and the police who serve them have no business knowing about it, then that is the rule they have set, in their house, with their absolutely sovereign constitutional prerogative to do so. No police authority extends over Congressmen in Congress, except insofar as Congress itself grants that power, and Congress can change the rules however it wants. It's a very important principle to prevent an angry President from doing to Congress what Lincoln did to the Maryland State Legislature to prevent a vote on secession (he arrested them in session). Can't do that using the guards in Congress. THEY answer only to Congress. Not to the President, and not to the Supreme Court. Congressmen want to carry guns. The capital police have nothing to say about that, and there's no reason to think they should have any veto over it. It's none of their business. They SERVE Congress. They do not police it.