Comey gives long statement and extensive testimony about how there was no way Clinton should be prosecuted for what she did with her emails. Clinton haters respond with disdain, skepticism, and challenges to her impartiality, and some outright disbelief.
Comey gives one sentence quote about how she "may not have been sophisticated enough" to understand certain markings. Clinton haters immediately take his word and his opinion as gospel.
If I didn't know any better I'd say his credibility in your eyes is conditioned not on his qualifications or his reasoning, but simply on whether he's saying something that inflicts maximum damage on Hillary Clinton! That can't be it, though. You guys have way too much integrity for that.