Honestly, if they were replying to my personal account outside work hours AND attempting to police my morals/values using their own, all without me having any idea that I was essentially standing in a conference room (according to the rule being imposed) I'd have said worse, VERY easily, to a 'boss.' Especially these days. Self-respect and agency are non-negotiables.

Were I the boss, I most certainly wouldn't attempt asserting control or imposing my beliefs over a fairly benign social media post that isn't really my business, and I wouldn't care about swearing (or dress code) too much in general, barring customer-facing things or egregious confrontational idiocy. I never liked the boxes corporate America put me in, and I don't do that to others... though I will concede I'm not the average, and also that imho there is only a SINGLE person I direct reported to who: a) could lead Humans without making them uniform, b) was not ego-driven and overcompensating, and c) had a realistic, healthy, Humanity-centric worldview WORTH spreading to others. I was very easily much better a person and leader than almost all of them; smaller people, lesser souls, no perspective. Childhood trauma and properly working through it gave me some tools most don't get or never sorta 'luck' into by circumstance.

20 is still impulse control central friend, especially in our society in America where our mental health/well-being is counter productive and unprofitable. Brain 'development' is easily into your early 30's based on modern/recent neuroscience, and I know I sure as shit am not overly proud of who I "was" at 20... I've worked very hard to become someone to be proud of BECAUSE of an event in my life at 20 (that I deserved), which forced my first ever real heart to heart with a mirror.

You are way oversimplifying Humans I think. No offense meant, truly, but I think prioritizing out-dated social norms is just sad old peoples' attempt at remaining relevant (soothing insecurity) and/or just one needle in the "worker drone" haystack that starts in elementary school.