I wonder how many schools in my country are teaching these kinds of topics. I asume it is being taught in most schools around the world as part of classical literature or folklore.
One of the things I find more fascinating about Greek mythology (I say greek because it is the most widely known, but similar stories can be found in most mythologies) is how easily it can be associated to human psychology and the different developmental stages.
All the dramas and intrigues we all go through have been somehow illustrated in some myth.
Regarding how we interpret these creatures, I agree with you in your assessment

one wonder if all the Giants folklore is nothing but a cautionary tale for us humans, telling us not to rise against the skies if we do not want to share the giants’ fate?

We hear the word giant associated moderly to great people, of great intellect or ingenuity who have raised above the crowd and even though they may inspire admiration they are often the object of intrigues and attacks, precisely because their achievements tend to question or challenge the status quo or some dogma that dominates a given society at a given time.

I also think that giants, like many other supernatural or fantastic creatures present in oral traditions and in some religious texts are nothing but the result of our ancestors' imagination and inability to put in words something that in their time they could not quite grasp.

I try to imagine what it would have meant for people averaging 5 feet high to be in the presence of a 7 footer. Even today, with so many super athletes that tall, we can't but feel mesmerized in their presence. It was understandable for our ancestor to exagerate the feats of people that big or strong.