Get your downvotes ready boys and girls. ;) Here's an honest answer from a real life dad with elementary aged kids.
tl;dr - Not everyone has the same values as you and businesses want to make money.
First, you must understand that different homes are not like yours. Sure your parents might shout obscenities towards each other when they're arguing. Mine sure did! Some parents might even be cool with their kids swearing. But then there are homes like mine where I don't shout obscenities at my wife... ever. I don't swear at my kids... ever. And I understand this gets people angry because I'm some sort of goodie two shoes, but wouldn't you rather live in an environment where you're not cursed at and disrespected? I know my wife and kids sure do. Yes, I get kids pick up a lot from school. I was a kid once. But shouldn't my home be a comfortable place absent of the bullying and cruelty of school? Judge me if you must, but I care more about what my wife and kids think of me than random people online.
Because of how I choose to run my home, if a game has a lot of cursing, I won't buy it. It isn't for me. It doesn't fit in my home. Businesses understand this, so they sometimes choose to soften the language a bit to get their game/movie/whatever into my home.
Let's talk about violence. Consider for a moment that you may be desensitized to the violence. For me, I want violence to be dramatic and tragic. When my family sees violence I want their brains to immediately think, "This is a bad thing". So I don't buy a lot of violent games. I especially never buy games that require cruel and unjust violence to progress. To put it in perspective, "Phoenix Wright" - Okay for my home. "GTA V" - Not okay for my home.
And finally, let's talk about sex... baby (sorry, couldn't help the dad joke... which was probably lost on all of you born after 1995). To me, women are not objects for my pleasure, but real humans just like me. A game can be made without sexualizing a woman for no reason at all. I don't want my son to grow up thinking of women as a lessor human, but rather a compliment that is equal in dignity to him. Let's admit it. Some games are just as playable without the heroine running around in her underwear. And the plot makes way more sense when women are dressed appropriately.
All in all business want to make money, so they make business decisions to get their product into my home. This is good for you because games that don't sell don't have sequels.
For me, I would like a dynamic censorship solution. A way that both parties are happy. One where I can say, "Here's how much sex, swearing, drug use, etc... that I'm comfortable with" and the game simply adjusts. I lower the meter to more tame and women get appropriate clothes and say "dangit" more. :D You can leave it where you want.