I once interviewed a pair of American linguists who specialize in sign language for the deaf. The Nicaraguan government contacted them shortly after the revolution there to ask them to come give advice on a school for the deaf the new government has established.
The school was for very young deaf children and had no teachers. The social workers running the school noticed that the smaller children, in the absence of language, were inventing their own.
The linguists rushed to Nicaragua and intervened to make sure no attempt was made to teach the children another sign language, and instead learned the children's. It created a huge sensation in the world of linguistics, because no one had ever (or has ever) seen a new language being born.
But we all have the innate drive to make language. Children learn to talk not because their parents teach them to, but because at a certain stage, they're ready to.
And one thing the linguists learned was that, as part of it, the kids invented slang. They had proper names and nicknames for people, they had scandalous words, silly words, and formal words, and they knew which was which and when to use them.
Slang is hard-wired into our language-making ability. It's not new, it's not strange, and it's not going away.
And who would want it to?