1)
Who says this?
1.
Malbim: The verse depicts that Hashem screams this among the litigants, and warns the judges with them, and also amidst the judges. It speaks as if the judges' ethical Nefesh testifies to them in their hearts in the name of Hashem that they do improperly.
2)
Why do they favor the Resha'im?
1.
Radak: They are strong, esteemed and rich; judges favor them, and do not judge cases of the poor against them.
2.
Malbim: There are two ways of tilting Mishpat. (a) A lender and borrower come for judgment, or a buyer and seller... - "Ad Masai Tishpetu Avel." (b) The judges ignore oppressors, extortionists and strongarms.
