There is a partisan political purpose involved here too. In US mid-term elections, the president's party almost always loses seats in Congress. When Democrats hold the presidency, the trend is particularly pronounced. Thus, the Democrat's hold on Congress is at risk in the next election. To counter this, some democratic leaders seek to use the media to discredit their political opposition.
House Resolution 503 was Nancy Pelosi's attempt to launch yet another political media event supporting her domestic conspiracy theory that the attack was a preplanned and coordinated assault on democracy. It is a continuation of Pelosi's efforts to paint Republicans and other Trump supporters as severe threats to constitutional government. Her resolution presupposes in its stated purpose the conclusion Pelosi wants, declaring that it was a domestic terrorist attack on the Capitol.
In announcing the resolution, Nancy Pelosi declared she already knew the "root causes" of the January 6 Capitol riot: “the white supremacy, the anti-Semitism, the Islamophobia, all the rest of it that was so evident when you see a sweatshirt on one of the people saying, ‘Camp Auschwitz.’” Based on a sweatshirt slogan, she repeated the common and yet completely unsubstantiated claim that the Capitol incident constituted an “insurrection.”
In a rare move, Pelosi personally sponsored the resolution almost six months after the events, and only days after the Senate's bipartisan 128-page report. The Senate report found failures in security, planning, and the response of the entities directly responsible for Capitol security. Moreover, though the Senate report repeatedly refers to organizations with counter-terrorist responsibilities, nowhere does it label the Capitol riot a terrorist attack, which hinders Pelosi's terrorist narrative.
After seven months of intense investigation, the FBI has found scant evidence that the Jan. 6 attack on the US Capitol resulted from an organized plot to overturn the presidential election result. (Source: Reuters.) Moreover, while Pelosi prefers highly loaded words like "insurrection," prosecutors see it differently: no seditious conspiracy charges have come out of the US Capitol riots.
While at least one member of the Oath Keepers has pleaded guilty to conspiracy to obstruct an official proceeding. That charge, under 18 USC §1512(c)(2), does not rise to the level of seditious conspiracy (18 USC §2384.) Some other charges against Oath Keepers near on absurd, that they "loaded into golf carts and began speeding toward the Capitol building." With top speeds of 10-25 MPH, golf carts hardly seem a rational choice for a paramilitary group, let alone for further inquiry by the house of representatives.
Nancy Pelosi's resolution goes beyond political oversight and seeks to change the rules that apply to how her personally appointed committee deals with intelligence sources and methods:
(a) Access To Information From Intelligence Community.—Notwithstanding clause 3(m) of rule X of the Rules of the House of Representatives, the Select Committee is authorized to study the sources and methods of entities described in clause 11(b)(1)(A) of rule X insofar as such study is related to the matters described in sections 3 and 4.
The abovementioned rules give the Intelligence committee exclusive oversight of intelligence sources and methods. The rules also require a degree of partisan balance on that committee: no more than 13/22 of the members may be from the same party. Access to raw intelligence products is generally denied to politicians for a good reason. And in HR 503, the attempt is not to provide congressional oversight of the intelligence community but to bypass the normal functioning of intelligence agencies to serve a partisan political goal: showing there was an insurrection and smearing the minority party before the next election.
Rep. John Katko (R-NY), who voted to impeach and worked with a Democratic House Homeland Security Committee colleague on a bipartisan bill, said:
I led the charge to create a January 6th commission that would be external, independent, bipartisan, and equitable in membership and subpoena power. The select committee proposed by Speaker Pelosi is literally the exact opposite of that. The select committee would have a skewed, 8 Democrat and 5 Republican panel of members, all 13 of whom would ultimately be picked by the Speaker herself. It would be a turbo-charged partisan exercise, not an honest fact-finding body that the American people and Capitol Police deserve. For those reasons, I will not support its creation when voted upon. Recognizing the deeply disappointing departure this represents from a truly bipartisan solution; I have a hard time envisioning a scenario where I would participate if asked.