I think you're taking this too personally. "Conventional wisdom" doesn't mean that everyone actually agrees with it, which is obviously the case here. One of the other posters said he was asked if there was anything they (the interviewers) DIDN'T ALREADY KNOW that he wanted to share with them. If it is on the application, they know it.
I think you are not giving adcoms enough credit. They see a variety of grade patterns from applicants year in and year out. If it is something really glaring, like a DUI might be, they would ask about it. I don't think something small like one bad grade or a few Ws is warrant enough for any school to dismiss you from consideration.
Again, I submit that if asked such a question as mentioned above, use the time to remind them of your committment as a student, dedication to their philosophies, your excellent community service experiences, etc. However, if you feel you must bring something up that you think may be a stumbling block to the adcom, mention it if it makes you feel better.