Hay Committee is not just an expense category of Ponyville Town Hall for tea and cookies.
It's not even an attempt at community outreach (if you told that to Mayor, she'd be bewildered by the idea you needed a special name for that).
And, of course, it's not a shadow council that rules Ponyville from behind the curtain.

Hay Committee is just a group of experienced ponies from all walks of life, whom Mayor Mare trusts to give her advice on municipal matters.
They discuss a lot of questions that are vital for Ponyville to thrive, such as railway station safety or proper Summer Sun Celebration decorations.

That would've been of no interest for us if they haven't started an amateur detectives club.