Because writing is a process suited to some minds more than others. And if your bar to receiving an idea is that it came from a competent writer then you’ll be limited to ideas that reflect a certain way of thinking (and one many mistakenly conflate with intelligence).
Conversation is a different process that may be suited to other types of thinking. And so on.
It’s true that LLMs can enable unoriginal and shallow thinking to be expressed with a false veneer of original thought. But it does not follow that all LLM-written text is the result of laziness nor that it is without value.
I’m just suggesting, come with an open mind rather than judging the whole thing based on a gut reaction to style. That reliance on a gut stylistic reaction is itself lazy and has led many an intellectual community into echo chambers of groupthink.
Why should I spend my time enabling someone too lazy to do their own writing? If I want to know what an LLM has to say, I can prompt it myself.