That is a pretty dramatic response to Meetup deleting a group. I've never created a group, but it seems the event WAS outside of the intended use of Meetup. It looks like poster was trying to use it to host a single event where Meetup wants you to create groups that meet and communicate regularly. To me, it looks like the poster was indeed using Meetup as a listing service. I think the telling piece of information th…
It's still surprising that the data was deleted instead of internally flagged.
The excerpt from the (apparently edited) Meetup response merely says, "Once a Meetup Group has been removed from the site, it's final."
That doesn't say anything at all about the state of the data. It may just be that they don't want to have to deal with appeals when groups are removed, so their policy is to make all removals final, even if the data are left untouched.