While you might be getting bacteria into your ear with the water, the more normal problem is that having a wet ear makes for a more hospitable environment for the bacteria that is already there ---- in other words, even if you were diving in pure distilled water it would probably cause problems for you.
Well said, Charlie. Why invite the varmites for a feast when measures can be taken to ensure the environment doesn't create a party atmosphere for them? If the bacteria is already there but they're behaving themselves, I can co-exist peacefully with them, but not when they "act up" at my comfort's sake. And you're right about any kind of water being a factor . Sometimes I used to get infections just from getting too much water in my ears after taking a long shower. It's dry ears for THIS woman! I'm just glad that not everybody has the same problems as some of us....otherwise there would be a lot less divers. It's good that people are coming up with ways to help the rest of us who are prone to problem ears able to join the "healthy ear" people under water!