It's a subjective thing - I couldn't agree more - and a very subtle thing too. I doubt that many of us could hear a performance and unerringly detect all the ways in which the performer's personality is couched within it. We just don't have the tools to do that. But (and I freely admit that I'm talking somewhat hypothetically here, never knowingly having heard the singer in question) this is a rather exeptional case. For one thing, these are not just predispositions. To put yourself forward as a candidate for election for a particular set of principles is to make a conscious decision to make these principles a significant, defining part of you as a person. So these parts of the personality are likely to be among the most influential. And secondly folk song is especially susceptible to manipulation by ultra-nationalists.

If someone sings a traditional song - and not one explicitly making the point - I think I generally get a good idea if that performer has a rose-tinted view of the past, whether they find a connection with the singers who have passed the song along (or, conversely, detatch themselves from that), whether they think of the originators of the song (or the characters withing it) as primitive or sophisticated (or as equals). And many more things besides. And all of these nuances come from the performer's personal make-up.

Moreover, in this particular case, we know the vile matrix through which the song is being filtered. Ultimately the conclusion about the content of the performance may well be subjective and my own, but it's real.