People want to know about LLM use for various reason.
I think the main reason is an ethical one. LLMs use a lot energy, datacenters are bad for the environment, people lose their job due to AI, LLMs are trained on stolen data. There is many reasons why someone would not want an LLM project.
And let's be real, there is a lot of issues with app being vibe coded and being shit real fast.
So when presenting a project to the world, people will definitely ask, and you can respond or not, and be on your way.
It's naive to think that people won't use LLMs, but it's also naive to think that people only care about the end results, especially on a platform where people are generally more sensitive to ethical considerations.