Maybe they were 'good' in a lot of ways. Not the poachers in the song, so much, but maybe for some, poaching and other desperate measures were the only way they could feed their families.
I think with the 19th century coming-on-strong of 'Mr Darwin' and resurgence of ancient 'eugenics' ideas [or maybe they'd never really gone away in the first place?]..... well-you know- like the kind of thing Alan Watt used to go on about ? : "The Darwin and Wedgwood families" and their interbreeding for generations until, according to him, they began getting some pretty 'inbred'-sounding results?

And I think it was Alan Watt whom I remember saying that, for instance, by the time E. G. Welles came along [and was very intellectually gifted] , the best he could hope for was to be kind of a 'life-peer' [?], but not join the ranks of the hereditary elite, because the planned speciesization/splitting of the human race by methods as outlined by Bertrand Russell, e.g.-

"Diet, injections, and injunctions will combine, from a very early age, to produce the sort of character and the sort of beliefs that the authorities consider desirable, and any serious criticism of the powers that be will become psychologically impossible." was already well-underway, it was believed 'on high' at least, at the time.
I hope this makes some sense, because I'm tired out now, both from trying to write it, and from how pretentious it sounds.