In the past and currently, there are lots of situations where the actions of one or more individuals provoke a reaction against an entire group, or when arbitrary problems are simply blamed on a specific group, and any members of that group are suitable targets. The fact that Rhode was a zealot and that the humans at least forgot about the Black Ring when they withdrew and focused on dragons may be illogical, but is hardly unbelievable.
That's true. Of course i would not be suprised if some of dragon slayers commanders were actually black ring agents installed to give slayers a "push" in right direction, since
one of commanders of seekers was demon worshiper, so it's possible.
Second, leaving they task of executing me to 'underlings' would be an entirely irresponsible action of my 'commander'. It would be like some manager telling 3 employees to go off and 'fire' one of their coworkers...
I think it was because we weren't full dragon knight yet, and since we were supposed to be her pupil she could't bring herself to do it.
In aleroth we meet her as fully developer dragon knight, probably with strong dragon aura, so that's make her call us "abomination" and want to kill us instantly.(Mot to mention that she probably knew what happened to others slayers since DK was alive.)