Comment by tombert
I think they're saying that "Libre" typically implies Copyleft, with a GPL or AGPL or MPL License. Something that (in some cases) forces you to make your changes available.
LibreOffice, for example, is Mozilla Public Licensed, which is a weak copyleft, like LGPL (I think).
It's just silly gatekeeping. E.g. LibreSSL is permissively-licensed and is from 2014.