The assumption is correct. Afghans are resistant to interference, and this NATO occupation seems to be going the same way previous attempts at interference have gone. It's not just negative opinion of US, it's negative opinion of US for a reason.
Facing heavy resistance does mean Afghans are against US. Not necessarily all Afghans, but vast majority.
For the last part, just like many other countries, opinions across the country differ greatly on things. In Pakistan, Iran, US, etc, and also Afghanistan. Again, it's tajiks who run Afghan government - not pashtun. Pashtun are greatly against US occupation or for that matter any outside interference. And those parts that are unsurveyed are pashtun parts.