User blog comment:The Dragon Demands/Season 4 second trailer airs/@comment-192.147.235.94-20140218044407

Re: your first point, Melisandre took away Arya's only friend in the world (in her mind) so as far she's concerned, the "Red Woman" is as bad as the others. She's probably assumed that Melisandre's killed Gendry.

I haven't read the books so I'm purely going by what I've seen on the show.