just seems like extremely poor communication and more "open letter" bullshit that's really a nothing burger. Seems like one or two people said "we're disbanding!" while based on some threads I've read the remaining team was like "yeah...we really didn't want to"

There is no remaining team. The two people who are resigning here are the entire team (originally it was four members, but two had already resigned previously). What's the point of having a team without any members?

just privately quietly resign

How are you supposed to "quietly and privately" resign from a community project that versions team membership and responsibility in Git? Genuinely, what are you imagining that is lower profile than this and not wildly irresponsible?