Betheists have a very narrow view of what actually ESL is. If you teach a certain language as
a foreign language, you will not only teach the linguistic side of it. Languages are
related to their language communities, their culture, history and sociopolitical
settings. This is a common definition Teaching German/French etc. to Second/Foreign
language speakers. For example, if you teach English Literature to Chinese students at
High School or uni, it is ESL. If you teach a course in American Sociolinguistics on the
sociolect of Afro-American English (to avoid the more racist term "black"), it
is also ESL.

Definition:
ESL is everything that

a) in some way relates to English, its language and language communitie(s), culture, language
system (Linguistics) and Literature, way of teaching (ESL Methodology), and Translation

and that

b) you teach to non-native speakers of English.

There are area in ESL above or beyond purely practically related language courses. Years ago,
Cambridge ESOL has had an exam "Diploma in English Studies", which mainly
covered English Literature and did not cover/test any practical language skills. I don't
know whether it still exists, but I know for sure that it was available at some time in
the 1970s. Second, there were exams for something called "British Life and
Institutions".

Narrowing ESL down to the acquisition of practical language skills is an unprofessional
definition of what ESL actually is and mostly comes from people not sufficiently
qualified in its theoretical approaches and ESL practice. Ask a foreign professor
teaching a course in English Literature to Chinese English majors at a Chinese
university whether it is ESL or not....Hahahahhahhahahhahaha

A bit hard to understand for folks teaching at training centre level; the world of teaching
ESL at tertiary level is mainly non-profit and much more diverse than your "this is
a house" and "spell grammar with two m".