By that token, asking RMS about cars in relation to his attitude towards computer would be akin to asking whether he lives in civilization or not, since everything from traffic lights to voting machines don't have open software at all. The category error is one of scale, not technical advancement.
Example of a category error (stolen from Ryle): you are handed both the left glove and the right glove, and you ask where the pair is. The pair is not a separate thing from the left glove and the right glove.
'Category error' does not mean a quantitative or scale difference at all.
