Because she is an attractive female pure and simple, never a good thing to be on reality shows.
The exact same thing happened last year wit Nicola McLean last year, she was voted to do every trial, and if I remember correctly, she had EXACTLY the same reaction on the forums as Helen has had this year.
The same thing will happen next year, unless they bring in a rule, where if one person has done a trial, they are exempt from further trials, but ITV won't do that as they'll lose money on the voting.