They were there to disrupt the peaceful transfer of power of the government.
They came with weapons, human restraints (flex cuffs), and were calling out politicians they disagree with and explicitly looking for them.
The intention of several seems to have been to _at least_ take hostages if not worse. What would you call the threatening, kidnapping and possible murder of your political rivals for the express purpose of keeping your side in power? If that's not a coup I don't know what is. That they failed doesn't mean they didn't try.
I think part of it isn't really in bad faith, it is just some sort of magical thinking, along the lines of: "a coup is something that happens over _there_, those places we see only on the news".
That it wasn't going to succeed, doesn't mean it's not an attempted coup. It's a self-coup because they were told to go there by Trump, after Mike Pence told Trump he couldn't do what Trump asked him to do, which was to just declare Trump the winner. i.e. ignore the state ascertained Electoral votes.
This is an autocratic movement. The legislature is an impediment to that. Maybe they envision a principate to give it the veneer of authenticity that an outright autocracy would not. That worked for the Roman Empire for ~250 years, people bought that it was still a Republic when it's plain to history it was ruled by an emperor during this time.
Of course had it succeeded, no matter how it had, Trump would have accepted it happily. He doesn't care about the Constitution or even the veneer of legitimacy. He just wants to win. Doesn't matter how.
