The stimulus in this question is written intentionally poorly to mislead the test-taker and that is simply unfair practice. The use of Hence in the conclusion is semantically wrong and that which causes the confusion. Instead the stimulus should be written like this:

"The miscarriage of justice in the Barker case was due to the mistaken views held by some of the forensic scientists involved in the case, who believed that they owed allegiance only to the prosecuting lawyers. Justice was thwarted because these forensic scientists failed to provide evidence impartially to both the defense and the prosecution. That being said, it is not forensic science in general that should be condemned for this injustice."

That is frankly bad writing, and any book/magazine editor worth their salt would fix that problem.

4/5. Got the new interface today, have yet to adjust to it.

Wonderful! How have you been studying? Have you been mainly drilling?