Why so many leftists hate capitalism and their own countries

Over the last few decades it has become more and more common for a significant portion of the population, especially those on the far left end of the political spectrum, to hate, loathe and detest their own countries, their own nations, everything around them, and the system that keeps the system running.

There are quite many reasons for this, but many commentators have presented one quite good hypothesis why that is:

It's a massive case of "you don't appreciate what you have until you lose it".

They note that the current generation of young-to-middle-aged adults is the first generation in a long time that has not only lived in luxury their entire lives, but also their parents have lived in luxury their entire lives.

The previous generation had parents who lived through the wars, and experience first-hand what it is to live in actual real fear, in actual scarcity, in times of uncertainty and massive shortages, where not only could you not be sure you could eat the next day, but in fact you couldn't even be sure you would be alive the next day.

That generation learned to be very grateful for what they had, when the big war was over and society started rebuilding and growing once again. And that generation, having first-hand experience, inculcated that gratitude onto their children.

But then, those children became adults, having never experienced any hardships, and their children had children of their own, having never experienced any hardships, so most of them never felt the need to inculcate those hard lessons onto their children.

Thus, we arrive at a generation that was never taught about hardships and to be grateful for the luxuries and abundance they live in. And what happens? They are ungrateful brats who take all the luxuries and the easy life for granted, and can't even imagine a life where they have nothing.