My answer to: (To vote and comment on Quora, visit the link here.)
I will give an explanation from a point of view of a society in some parts of which, such words are still taboo in both theory as well as practice.
In the most close-minded and conservative of societies, a “taboo” basically means when you grow up, you still pretend you haven’t developed knowledge about a certain concept (Remember, “pretend” is the keyword). Except probably to friends. But that pretense exists in your interactions with family, relatives, etc. Example, you may realize about sexuality at an age such as 13, but you may never explicitly talk of it to family ever in life. You are averse to even drop a hint about it.
With that explained, let’s come to slang. Suppose you spot a blog post which uses the word “motherfucker”. The blog post is otherwise so great that you want to refer it to an elder sister with whom you share that relationship where pretense based on taboos exists. The keyword, as I said earlier, is “pretend”. Now when your sister is reading the post, and she reads the word “motherfucker”, the taboo relationship breaks, and there is embarrassment to both of you, even if not face-to-face.
Imagine what if that word is written as “motherf***er”. The sister is reading it. She understands its meaning. But, she has that relationship with the younger brother where taboos exist. So, she wants to think that the brother had not understood what the asterisks mean. She pretends that the brother does not yet understand. She gives him the benefit of doubt. The brother, meanwhile, because of asterisks, finds it easier to refer the blog post to the sister, because it helps the “sanctity” of their relationship to remain. He pretends that it’s the sister who does not understand what the asterisks mean, and hence expects she will ignore it.
The same theory works with beeped expletives on TV shows. That’s how strong taboos work. Beeps and asterisks facilitate pretense resulting in benefit of doubt; and they help preserve the sanctity of relationships in various societies. So even if everyone knows what the beep means and what the asterisk means, it’s sensible to always use them in pieces of art such as movies, TV shows and newspapers, because art caters to all kinds of societies.