they are contextual expressions often emphasizing an abstract though equally shared reality -- emotional states. sorta like how "doch" functions in german sometimes. and i definitely will debate it being universally understood semantics, esp for native english speakers.
do you know many people who interpret the emotional weight of "that's fucking stupid" versus "that's stupid" as the same?
anecdotally everyone in my worldview would react differently to both, and further reactions will depend largely on how it is said -- not because of some ambiguous meaning collectively (mis)understood.
i have always found people who want to wipe clean the slate of language and all its slang and "offensive" words in favor of established definitions and order -- contextually or otherwise -- often lack a lot of emotional expression in their correspondence.
people emote. physically and verbally. and we have all kinds of mechanics to capture the nuances in contextual languages -- slang is one of the best features, and the nuances can run super deep, nuances a lot of formal writing or correspondence can lose in its rigor and strictness. especially not withstanding cadence and emotion.
youre going to have vastly different experience reading stevenson and then say twain, for example. even speaking it aloud -- but i encourage you to spot a common denominator.
their dialogue often reflects the character, the context, and the emotional state, and largely not formal. and there's a heft amount of literature that utilizes formal writing in its dialogue, and one of the first things lost in the narrative is cohesion, and therefore immersion, bc that's not how most people speak -- only a distinct subset talks like that culturally and even then it is still not totally real life.
humans are very rarely strictly formal in correspondence in practice -- we only established professional dialogue as a norm to separate the haves from the have-nots, and then made it a moral high-ground to keep the "peasants" in line.
express yourselves. say what you mean. stop letting people convince you that you should be scared of saying something like "that's fucking stupid" bc it means more for you to say "that's stupid" for the sake of arbitrary professional standards.