Whenever anyone tries to force you to pick a side, the best answer is generally "not yours". Why should Kazakhstan not follow that principle here?

By doing this, the US is effectively pushing them into China's arms.

Disagree with you. Sure forcing sides is bad business, granted. It's not really even worth saying imo. But it's like the prisoner's dilemma. Once the other side makes their suboptimal choice, you're now-optimal choice is the other suboptimal choice. The US actions aren't in a vacuum, they're the US making a suboptimal choice in absolute terms, because it's the best choice is relative terms.