Why is it ok for that paper to dig up dirt on uber, but not ok for uber to dig up dirt on the paper? Is it because it is done as retaliation? If uber had start

Why is it ok for that paper to dig up dirt on uber, but not ok for uber to dig up dirt on the paper? Is it because it is done as retaliation? If uber had started to dig up dirt first would that be ok? Or is it because only media is allowed to dig up dirt? Would it be ok for uber to pay another newspaper to look into the first one?