That's the whole point of the adversarial system. The prosecution finds experts that state one opinion, the defense finds experts that say a contrary opinion, the juries pick out whose opinions they want to believe. That's the whole point of expert witnesses - they are the only witnesses in the courtroom who are there for their opinions.

The problem is that one side of this equation has a cottage industry of well-funded experts to pick from, but there isn't a cottage industry of well-funded 'bullshit debunkers' to work for the defense.