Wudric, your questions are entirely justified and your analysis spot on. This 'competition' like most of the other shows in this genre, ('The Great British Bake off', Pop idols or whatever it is that cowell creature produces) is dictated by baser instincts than fairness.
The results rarely have anything to do with who is more talented or produces the superior result/product, but are more clearly related to primitive/primal tribal affiliations. (middle class, white, working class etc. all being tribes).
The 'Strictly' audience and judges vote for people who reflect themselves, thus affording themselves the opportunity to bask vicariously in their pseudo-winner's glory, much as if they themselves had attained the victory.
So miniscule is their actual self-confidence that to recognise someone who doesn't immediately reflect themselves, as superior in talent, in their sub-conscious, would be tantamount to kicking themselves in the teeth.
They will continue to ridicule your questions, instead of conducting some serious introspection; and they will continue to make excuses for obvious injustice.
And as a result we will continue to perform at inferior levels as a country, whether it is on the sports field, in the music industry or in the political arena. Countries like the USA, that do a much better job of embracing and celebrating talent, whatever the hue of the talented person, will continue to lead where we can only follow.
It is impossible to truly improve when one doesn't recognise superior talent and instead consoles and rewards oneself with false accolades. If people could simply be more honest, recognise someone else's superior talent regardless of their race, and then work like a maniac to achieve and eventually surpass that talent, we would all be improved as a society. Instead we will remain deluded, narrow-minded, middling, unremarkable......... and bask in it.