However, all three former presidents and their spouses, except Michelle Obama, will attend Trump's swearing-in ceremony.
Couldn't pass up the more prestigious event that's going to be watched by the entire world.
In comparison, passing up a work lunch with a bunch of congresspeople that probably won't even be televized doesn't sound like taking much of a stand against the fascist takeover..
They still think it's Presidential to follow pomp and circumstance to preserve the appearance of national normalcy as the nation burns on multiple fronts.
Just as in their Presidencies, they want to be known for promoting social quiet, despite their Presidencies all defending and furthering economic violence in the name of all their wealthy friends who "donated to" their respective parties over the years.
It's not like they don't have TVs and/or stream-capable devices. There's only two reasons why anyone not directly involved in the proceedings would want to attend:
To hang out with elites.
To be seen as elites.
It's very much the US version of a royal coronation: tons of ridiculously expensive pomp and circumstance paid by and mostly for the benefit of people who don't know the price of groceries firsthand.