You can indeed attend and raise concerns but it will likely be ignored. Nobody is worried about losing their seat if they ignore constituent complaints.

Yeah, I don't really know how the Chicago school board meetings go, but I watch the MTA board meetings. (The MTA is New York State's public transportation agency.) They have a public comment section where you get 2 minutes to say whatever you want. These rants are usually completely incoherent and I doubt any board member could remember a specific point from any one of the commenters. I watch them all and I certainly can't. The law requires that you be allowed to speak. The law does not require the board to take any action on your comments, or even remember a single point you tried to make. ("I've said it before and I'll say it again. Democracy simply doesn't work.")

That said, my advice here would be to keep it short and non-emotional. You can speak for two minutes, but you don't have to use all two minutes. Say what's wrong, what action you want the board to take, and how interested board members can get ahold of you.

Out of curiosity, why do you watch them all? Especially if you can't remember anything?

I watch the comments sections, even if they're silly, to see if anyone has anything interesting to say. Someone might, someday.

I watch the board meetings in general because the subject matter is interesting and there are neat details in there that don't get widely reported. Recently they had some slides with security camera footage of someone riding their bicycle on the subway tracks. No idea people did that. Also, the point of the board meetings public is to provide the public with some oversight. If you don't actually watch them, then there is no oversight. (I guess we hope that "someone else" does this for us. Transit reporting is not what the best journalists necessarily end up doing.)

He is probably not watching the public comment section closely, but the other parts.