The algorithm wouldn’t have a bias vs conservatives because it doesn’t include semantic meaning, but it could have a bias vs methods used by this conservative. Which really just comes down on whoever is generating those emails.
I don't know if it does or doesn't, but Republicans and Democrats use different keywords, not just semantics. For example, 'law and order', 'police reform', etc. It's certainly possible for ML to pick up a bias in the presence of such differences.
They also quote each other, without context it’s just word choice not the message. Considering messages are already tailored to different kinds of voters, spam algorithms are just another part of messaging.
What organizations are you thinking of? I'm not an expert in the area, and ones I know of are ActBlue that works only with Democrats, and WinRed which is the Republican clone.
