Richard - it comes down to whether you'd rather be right and offensive, or wrong and well-liked. Or, in this case, offensive and mostly right but partly wrong, or well-liked and mostly wrong but partly right.

The only way I would be willing to defend blacking up for Morris would be if (a) it was an ancient and unchanged tradition and (b) I was convinced that it had no connection with minstrelsy. Neither of these is true. Border has displaced other styles of dance in the revival within the last 30 years (i.e. post-Sex Pistols) - and there's plenty of evidence of overlaps and borrowings between older blacked-up dance styles and the minstrel form.