Tell him to do something about it then rather than rant at you.
All planning applications have options for public comments.
No not all men are like this.
My H, and a lot of the men we know, are in their 50s and still enjoy life, don't rant or doze, snore a bit but just a bit. They discuss current affairs but rant and do nothing no.
Generalisation here but seemingly accurate in our experience, men who are content, have fulfilling jobs, happy home, spend little if anytime on social media, get their news from more broadsheet sources, have hobbies they enjoy and put time into their children and families, like debating accepting they might change their mind, so are open to other people's points of view, are the ones who don't rant.
Ones who think they are right "end of" rant. They are tedious to be around.
So if he feels so passionately about this planning application, that's a good starting point for him to get involved with local issues. It might become the start of a whole new lease of life. Suggest he does something then OP or shut up about it. It really is what you do that matters not what you say. So cut off you as his sounding board. He'll soon shush.
Actions speak louder than words. Quite true.