And I suppose you want to hear that you are imagining these things
Fair, bad phrasing. I changed it to "ought have some steering power" which is the sort of language used in the rest of the post anyway.
That is a more precise statement of what is being pointed at at the cost of some laconicism, yes. I endorse this rephrasing for clarity.
Sorry, I am confused. I agree that there are costs to removing fences, and I do not think that doing so is a good general policy. I do not see how this is weighted against a cost of respecting fences however (this is outside the scope of the post, but not respecting them is both hard, since the other person can usually just walk away and also something I can only see being justified under extreme circumstances). To my eyes, the post only points out that there is a factor which usually isn't considered when erecting a fence, and that it should be weighed accurately. The scales weigh heavy in the example case, but this is because its purpose is to illustrate a situation where that hidden factor matters significantly. Maybe the fervour on that front bled into the general argument somewhat, but while I think that it is difficult to justify this specific public fence, this is not remotely true of all fences anywhere. If it were that simple, if I believed this to be absolute, I would not call to weigh the costs, I would call to stop.
The energy stored within the nitrogen triple bond, one of the strongest common bonds in chemistry, is ~10 eV which is a bit more than 15*10^-19 J. This is considered *very stable*. It is quite the feat for some biological processes to be able to break this bond. Now, an average human punch confers around 150 J of energy. So, if you had some very strange means of directing that energy, punching the air could split around 10^20 nitrogen molecules which is around 4 ml (4.65 mg) at room temperature.