As far as I can tell, they doubled the requirements. I do not see how that is targeting one specific candidate or how it is a 'fix' for anything. If you cannot hit 2% in a national poll you really should not be on stage. They have to have someway of narrowing down the field throughout this entire process.
The real candidate hurt in narrowing the field is Biden anyway - the most likely establishment pick. He wins by default should the field remain as it is, splitting the hardcore lefties vote among many candidates. Narrow that down to just a few and Biden may face real competition.