I am not that familiar with dog rescues groups but I have been a yorkie breeder for over 16 years so I will give my opinion on that portion. Here is a good article for you to read:
http://www.pupcentral.com/different_...f_breeders.htm
Anyone can be whatever kind of breeder they want to be. You just need to think long and hard. My recommendation is to be the best you can be. Raising dogs is a serious commitment and not to be taken lightly.
The reason to spay a female is not so much the concern for cancer but the concern for pyometra (uterus infection). As females get older they are more prone to getting pyometra and it can be life threatening. Also with females you have the mood swings they go through after each heat cycle. Having intact males and females in the same household can be very nerve racking.
When you get a lot of dogs together (males and females) you have to be prepared for dog fights if they are not altered (sometimes even if they are altered).
You say if you breed your female you will keep all the puppies. What if she has a big litter? Will you get those pups spayed and neutered when they get older? Think of the nightmare there will be if all those intact dogs are running around if you don't have them altered. Also consider the cost of feeding them, vaccinating them, and providing them vet care as they get older.
As for pet rescues, it is my guess that there are different types of pet rescue groups just as there are different types of breeders. I imagine there are good ones and some that are not as good. To me those pet rescues that tend to the medical needs of the dogs and are very particular about who they place the dogs with are the best in my opinion. Those rescue groups are no different that a reputable breeder that screen prospective buyers for the pups they sell.
There will always be offensive people out there. You cannot judge all people, be it a breeder or a rescuer, by the actions of a few.
I do hope you come back for more discussion. We all have different opinions on things. We can all give you our best advise but in the end it is solely up to you to do whatever you choose.