Objectively speaking if they left years ago there is chance they are describing the actual availability of toilets as this was really low in some states (some states with under 20% having access to toilets) https://en.m.wikipedia.org/wiki/Indian_states_ranking_by_ava...

Afaik dealing with the shit was left to dalits, leading to their outcast status. So if one was a dalit in low-toilet-availability areas then ’shithole’ is actually a really accurate depiction of their objective experience and not a derigatory expression.