Read the twitter replies for yourself if you have the spare holy bleach.
I honestly never understood the need to fire against the other idol when the dating rumor hurts them both - and the smoking gun is in the third party rumor mill's hands. I want to take the time to be an irritating preacher of fine internet conduct and say a lot of things are not worth saying, not worth thinking, and not worth to even engage in. Promoting divisiveness may distinguish you according to some tenuous interpretation of the fandom you consider yourself a member of but ultimately it causes rifts, potentially with more mature or inclusive members of your own fandom.
There are various reasons one might post divisive comments but Occam's razor paints a mentally draining picture that one felt that they would garner support from their own fandom or gain recognition as a defender of their idol, however the best defense is to not be in conflict in the first place. Bullets miss you when you are physically absent.