When the filters themselves aren't transparent, it is a major issue.

I would gladly prefer a "pre-filtered" list, as long as I could tweak it. For example, if I'm searching for viewpoints that don't correspond with my political views, it'd be nice to be able to find those by disabling the "political bent" filter based on personalization.

To not do so is to constantly wear rose-tinted glasses... pleasant, but ultimately, dangerous.