Why is the US and NATO letting Karzai strong-arm them?

I just don't get it.  It's like the USA and NATO powers are on their knees begging Karzai to take their money and the possible lives of their soldiers who would be stationed there for the next decade.  Can't they see that Karzai don't want the West meddling anymore in Afghanistan?  Why insist on helping a nation that does not want your help and flings your gifts right back into your face?  I just don't get it!!

Ron Paul writing at RonPaulInstitute:
...After a year of talks over the post-2014 US military presence in Afghanistan, the US administration announced last week that a new agreement had finally been reached. Under the deal worked out with Afghan President Hamid Karzai, the US would keep thousands of troops on nine military bases for at least the next ten years.

It is clear that the Obama Administration badly wants this deal. Karzai, sensing this, even demanded that the US president send a personal letter promising that the US would respect the dignity of the Afghan people if it were allowed to remain in the country. It was strange to see the US president go to such lengths for a deal that would mean billions more US dollars to Karzai and his cronies, and a US military that would continue to prop up the regime in Kabul.

Just as the deal was announced by Secretary of State John Kerry and ready to sign, however, Karzai did an abrupt about-face. No signed deal until after the next presidential elections in the spring, he announced to a gathering of tribal elders, much to the further embarrassment and dismay of the US side. The US administration had demanded a signed deal by December. What may happen next is anybody’s guess. The US threatens to pull out completely if the deal is not signed by the end of this year.

Karzai should be wary of his actions. It may become unhealthy for him. The US has a bad reputation for not looking kindly on puppet dictators who demand independence from us.

Yet Karzai’s behavior may have the unintended benefit of saving the US government from its own worst interventionist instincts. The US desire to continue its military presence in Afghanistan – with up to 10,000 troops – is largely about keeping up the false impression that the Afghan war, the longest in US history, has not been a total, catastrophic failure. Maintaining a heavy US presence delays that realization, and with it the inevitable conclusion that so many lives have been lost and wasted in vain. It is a bitter pill that this president, who called Afghanistan “the good war,” would rather not have to swallow..........