it got that territory in the first place by invading those places and suppressing the local people.

Suppressing? They grew in numbers and their standards of living increased under our rule and in the 70s there were strong efforts to put an end to all racial discrimination:

By the early 1970s, the Portuguese authorities had fully perceived racial discriminatory policies and lack of investment in education as wrong and contrary to their overseas ambitions in Portuguese Africa, and willingly accepted a true color blindness policy with more spending in education and training opportunities, which started to produce a larger number of black high ranked professionals, including military personnel.

http://en.wikipedia.org/wiki/Portuguese_Colonial_War

I feel like it's acceptable for the local people to want to have their own countries and not be ruled over by foreigners.

The majority of the locals didn't care strongly for independence, they were fine being ruled by Portugal.

and forced the local people to give up their natural resources.

That's such a simplistic version of colonialism... We did much more than just take resources, we brought our religion, language and culture to the native people which lived in a far more primitive state than us. We built lots of infrastructure (much of which is still used today because black governments can't do fuck all) such as hospitals, schools, roads, dams, universities. WE built those countries, not the locals.

We brought civilization to those lands and when we left we took it with us. Decades of bloody civil wars, starvation and misery is what followed in Angola, Mozambique and Guinea. Even today they're still plagued with problems and "their" governments are oligarchies of the worse kind who don't even come close to matching the quality of Portuguese rule. Funnily enough, the foreigner leadership actually cared more about the locals than the current local leaders do.