I think OP is claiming that if enough people are using these obfuscators, the training data will be poisoned. The LLM being able to translate it right now is not a proof that this won't work, since it has enough "clean" data to compare against.
If enough people are doing that then venacular English has changed to be like that.
And it still isn't a problem for LLMs. There is sufficient history for it to learn on, and in any case low resource language learning shows them better than humans at learning language patterns.
If it follows an approximate grammar then an LLM will learn from it.
