Haven't seen the routine, and have no intention of doing so - but this simply due to the fact that dance troupes bore the bejesus out of me; if you've seen one you've seen them all.
However, BGT is the very definition of light entertainment, so a political statement, and make no mistake it was definitely a political statement regardless of what the dancers have said, has no place on a Saturday evening entertainment show.
As far as the complainants are concerned, I strongly suspect there's a lot of bandwagon jumping - once the ball starts to roll, people love to join in.
I remember as though it was yesterday the (very very funny) Jonathan Ross/Russell Brand/Jonathan Sachs furore; this was a fairly late night radio show, which I happened to be listening to as it happened, and there were a few complaints...until The Daily Moan got hold of the story, and within a week there were 50,000 complaints, the vast majority of whom most likely hadn't heard as it went out, and therefore they either went out of their way to listen to it just to be offended, or they didn't listen to it at all but just felt they simply had to complain.
Frankly, it was pathetic.
So I wonder how many of those who have complained actually watched it as it happened, or have since watched it just to be outraged.