It took me a while to figure out what the outrage was.
The colors have been inverted. I know this seems to be somewhat ridiculous to point out, but I had to consult Wikipedia to contrast the image of the proper UK flag in their article on the UK with the keychain image to figure this out.
You see, I'm an American. (I'll get my coat when I'm done saying my thing.)
I couldn't figure that out from the article, because it is not mentioned at all, in the article text, nor by means of a comparison image, because none were provided. To my eyes, the shape of the flag looked correct, and I could not immediately identify what the outrage was, as the article no doubt expected.
It was a bit of a disservice, honestly - foreign readers may not be intimately familiar enough with the Union Jack to discern whether the colors have been swapped (how many of you would immediately recognize if the blue and red were swapped on the Stars and Bars,) but also the article would seem to confound those with color perception impairments unable to tell the difference between red and blue, to say nothing of those with no sight whatsoever who have the article read to them by their computers, or those who browse without images.