In this, you have to look at the reality of the situation.
There is not a public meeting about the "new stadium", there is a propaganda campaign designed to ease people into the idea THAT THERE WILL BE A NEW STADIUM, and they want to give a place where those "angry people" can express their anger and frustration, where it will not actually get to the public. Further, it appeases the masses when the politicians say, "you had your chance to vote, voice your opinion, etc."
The new stadium has already been planned and financial backing has already been acquired and the project is moving forward before anyone in the public knows about it.
So, going to the meetings is just an exercise in frustration. And all the people there and angry are looking for a way to win their argument. You cannot change their minds. They are frustrated and angry and focussed upon what they think is the problem. They are not receptive to radical shifts of perspective.
I have not had any success in the small number of meetings that I attended. In a different setting long ago, I attended meetings for a year before the one Libertarian lady started making sense to me. She is one reason that I eventually found my way to voluntaryism.
There might be some kind of simple message that appeals to some people who already oppose "spending." I'm trying to find simple statements or appeals that start people thinking in a different way. Maybe that effect does not happen until a year later.... yes it is frustrating, and I wouldn't expect immediate results.