It’s not against the philosophy, but it’s difficult from a technical point of view because there is no central instance that saves information about the group. And it’s difficult to keep the member list in sync (i.e. consistent) across all members, also having a list of administrators will make things harder.
Also, e-mail isn’t really suited for large groups, anyway, because you will hit spam filter limits at some point.
If you want a large group which you can control, you will have to create a mailing list currently, e.g. with Mailman.