It's not the cork that causes the wine to oxidize. It's the oxygen in the air that does that. You have to remember that the wine is in constant contact with the cork while the bottle is stored, and in fact that contact is what prevents the wine from oxidizing. For more, check this Q&A thread.
The problem, from my experience, is that cork plugs that fall into the wine are usually somewhat broken, and small pieces of cork are disconnected from the plug and float in the wine. So, what you need to do is to pour the wine, as lilly suggested to a carafe, but to do so through some sort of filter that will prevent the small cork debris from moving to the carafe to.