ESL as slur

I still have some serious issues with understanding American culture, but I don't really understand why the average burger thinks ESL is a slur.
This always confuses me, especially since I usually see it used by "leftist" or "woke" people who claim to love and respect all cultures.
Can you explain this to me?
Thanks.>>209499256
americans, anglosphere and their minions are huge retarded
/threads