You can! problem with facebook is that they keep changing the way they do these things, from both the app and the website.
So yeah, i partly agree with you
Anyway, this is how searching is working this week.. (from the computer website)
inside a group, search for the phrase.
Bottom left, you have the "source" field, by default it's set to all. you can select yourself, your friends, and a + button. there you can enter specific profiles names.
then you can filter by location, by date, order by popularity or chronological order.
you can do the same from the facebook app (android, don't know for ios)
type what you want to look for in the search bar on top. select the "group" tab so it will search inside the group. there you have the same set of filters...
regarding mailing lists, i used to be an avid reader (and sometimes even contributor) of the piclist when i had an hotmail account.. for many years they had a beautiful threaded view for mailing lists, everything sorted by thread and subthreads, messages only showed the relevant content... all went to crap around the time they launched windows 8 and updated the look.
