So...why is Star Trek discovery saying the word "fuck" such a big deal? (I ask as non-Star Trek fan here)

I saw a load of seemingly legitimate criticism about Discovery, and then it suddenly all became "It's bad because they said a bad word" which...seems far less legitimate sounding.

Hence the question, cos if there's some form of huge reason why them daring to say fuck is cursing everything related to Star Trek ever, it'd make sense to me.