Why is it that criticism of people's insatiable greed for wealth and power often gets dismissed with this thought-terminating cliche about utopias?

Desire to live in a society that's less greedy, that rewards compassion and punishes sociopathy is completely valid. We should be pursuing that earnestly because survival of our species depends on it. The people in charge are so drunk on wealth and power that they would rather drive our entire species off a cliff than sacrifice even 10% of their effectively bottomless wealth.

But instead of criticizing our current philosophy that's actively being taken too far and threatens to destroy us, you criticize people who express their frustration with this state of affairs.