If you can't communicate the principle, then it's not a principle any more. It's just personal judgement. It's "tacit knowledge".
https://en.wikipedia.org/wiki/Tacit_knowledge
Principles are the opposite of tacit knowledge, they are explicit knowledge.
> Being easy to understand is nowhere on it.
I don't understand what this sentence means. I don't know how to parse "on" in this context and it's unclear what "it" is.
> Why is it that everything must be dumbed down?
Are you saying that "easy to understand" means "dumbed down"? If that's what you're saying, I don't agree with that.
> If you take the GP's single paragraph that explains the principle and tries to use it to discuss a particular design, you will see that it's perfectly possible. The fact that people can't do the same if they read a paragraph less and stop at the name is not very relevant.
The paragraph was vague.
The problem is that the SRP does not help you communicate problems with code. It does not help you understand problems with code. It is too vague.
Following SRP does not help you write good code, IMO.