[javert]

If I had said, "Cars are used for transportation," would you say, "I know a guy whose car doesn't have a motor, but he sleeps in it"?

Or if I had said, "Tables are flat surfaces," would you say, "I saw a table in the museum of modern art that had a curving surface"?

So, yes, you are completely right, and I don't dispute what you're saying, but it does not invalidate the generalization. Analogously to the example cases I just gave.

There is probably some philosophical name for and explanation of this phenomenon, but I don't know what it is.