'I found a bug, therefore we should discard the entire system'; imagine it's a mature, complex, functioning system. If your CTO did it, you'd seriously doubt their leadership. The real question is, what are the outcomes we are choosing from? What is the outcome if we keep the system, and what is the outcome if we discard it? What would we replace it with - are we going to try to build a complex system from nothing? Are there third or fourth better options, perhaps improving the existing system?
The politicians have explicitly and repeatedly expressed their goals (see Trump's UN speech, for example): Undo international cooperation and jointly made rules, and create zero-sum geo-political competition based on power. It's fundamentally undemocratic and against the belief in the fundamental equal rights of all people ('all men are created equal') - i.e., that others should have an equal say. It also has a long and proven track record of leading to war, the experience of most of human history until the rules-based international order was built amid the ashes of WWII.
In this case it's backed by typical political talking points, designed to give people the impression that international treaties are generally bad and to rationalize the step they are taking toward their strategy. But as I said, it's should be transparent (and expected, though you never know which agreement is next).