When you're a contestant in a show that's watched by 14million people every week, then the only thing to do in a case of Twitter abuse like this, is ignore it.
Danyl strikes me as incredibly naive if he doesn't realise the repercussions of responding publically to asinine filth like this can only be bad.
The tweeters are anonymous he isn't. The tweeters aren't subject to their every move being scrutinised he is. To get into this kind of war of words is immature, and damaging.
I feel that Cowell has given up on him somewhat, to allow him to do this, just strikes me as indifference on his part. I'm not surprised X Factor is a popularity contest, I'm sure Cowell sees Olly as a better bet.
If the twins took Danyl's course of action against there online haters they'd never be off the internet, but they don't they are rather classy in that respect.
I'm sure it must hurt to have nasty filth spread about you on public forums, but the only thing to do is ignore it.