The intent was partisan, to remove representatives of one side to change the result of votes.
> Practically there'd be huge consequences for whoever was stupid enough to disrespect the US Congress
A few people have been arrested. I don't expect many of them to serve prison time. Those who organised this, encouraged it, sold tshirts with "Civil War 6 Jan" on, will not experience any consequences. And don't forget the president can still pardon them.
Selling offensive t-shirts isn't even remotely close to a problem. I too doubt they will experience any consequences.
Hopefully the violent looters and lawbreakers in the protest get prosecuted. But there are recent precedents on this issue; most of the protesters will have been peaceful and shouldn't suffering consequences for exercising basic freedoms.
The institution of Congress is critical. But the specific people in it at any time are important because of how they got there/who supported them on the way in and not because of who they are. They could be replaced and it wouldn't be a big issue, technically speaking. Practically there'd be huge consequences for whoever was stupid enough to disrespect the US Congress.