Of course it's always a good idea to learn things, like survival skills and gardening and whatever. And that a sensealble life style without living as a slave of a bank is better goes without question.
I can, however, see the point behind the remarks you criticise. It is true of course, that if you don't try, you have already lost. But I agree with some points the commenter made, in that you advise is not realistic.
Like this hunting and fishing and finding eatable things in the city . Yes, it is possible - it is possible now. Because nobody really is depending on it, and 99% of the people don't try it and probably don't even know about it.
But if things would get bad, and I mean really bad and not only for a few days - what do you think how long it takes until that even the last rat is eaten and the last dandelion plucked? With the amount of people living in cities today, it's not possible to keep them alive as hunter/gatherers or balcony gardeners. And at that point, they will move into the country side, but like desperate hungry locusts.
The life style you have now is certainly positive in view ecology, providing a healthy environment (also mentally) for your kids and so on, no doubt. But it also works best if the world around you is functioning. Whatever that means nowadays. But if it stops functioning, this very life style will make you a primary target for the legions of unfortunate, who also don't want to see their children die from starvation and who will do everything to prevent that, just like you do.