Most of my family is Catholic. Condoms, the pill, etc are just as forbidden as abortion. Not agreeing or disagreeing, just letting you know the doctrine. By doctrine, you can be excommunicated for using birth control methods (involving or not involving abortion). It is not contrary to doctrine to be supportive of birth control methods, but not use them yourself. In simplified form, you may express opposition to the Pope personally or Church doctrine (but you're technically not supposed to do so) and not get excommunicated, but you can be excommunicated if you act in a manner contrary to doctrine. Thought related excommunication is pretty much limited to heresy.
The reason why the Pope doesn't excommunicate Pelosi is the same reason he doesn't excommunicate owners or employees of companies that distribute or sell condoms. You could make a doctrinal charge that the distributors of condoms are more guilty of breaches of doctrine than someone that pro-choice but does not employ birth control methods themself.
