And why is it necessary to contest them?

The problem with this idea is that when you get down to ther kernel of it, the whole point of "contesting" someone's feelings is to override them and replace them with your own.

Like the guy with his wife. She says she feels abused. He says he feels he's not abusing her. Both are feelings, not based on objective fact. To get to truth, you need a common definition of the word abuse, paramaters around what falls into abuse (physical, financial, emotional, spiritual, etc) and an accounting of instances.

He may feel like because he never slapped her around, that he never abused her.

She may feel he did because she felt neglected and abandoned, inconsistency of affection, etc in the marriage, which would be emotional abuse. She may not have the vocabulary or self awareness to describe the whys of why she feels that way. She just knows she does.

So why does his feelings supercede hers?

Look through his stuff. He's a cold fish. I can understand why his ex might have felt abandoned in the marriage.