Curious thing your Soccer song. In a lot of cases nobody writes them down but they seem to be well known by all devotees.
Living in the southern North East we have supporters of several local teams and the ubiquitous Man. U. I've heard them all singing bits of terrace chants to "My Old Man" (Music Hall), "Hey Jude" and "If You're Happy And You Know It" to name but a few.                   Sadly there are some very "bad taste" lyrics in use but they seem to be in the minority.
Folk or Traditional ?? Dunno.