Convince your friends to come to Lemmy? If they don’t they really are not worth associating with.
What you want to do sounds like hosting a community that would mirror this community?
That’s easily done with using the “Create Community” tab in the upper left
I think they’re overstepping by wanting to know if people are posting bad things about the agency online, since no one wants to be spied on I can see how this would anger a lot of people