It provides "plausible deniability" for some. They can test out scenarios they've only kept in their head for social interactions and if it doesn't work out they can blame the drugs/alcohol. Personally, I used this to become more outgoing and sociable while in school and made it part of my core personality, but for some people being inebriated provides a "safe space" as it were to become that person.

For some, they mask in their daily lives while carrying tons of internal baggage and burdens and lowering inhibitions and letting that stress out manifests in different ways for different people and they get used to that release while in that mental state.

I bartended full time for a short period of my life and am still in the bar scene so I've seen a lot of different shit when it comes to this, but I say if they're not hurting anyone or themselves, let 'em cut loose. Life is hard as it is and reality's been especially weird lately.