And Pathfinder probably is but an extended typo, a brief lapse in Diane Duane's writing process for Intellivore.
Not at all. Diane quite explicitly described the Pathfinder as a ship that Picard had commanded between the Stargazer and the Enterprise. I considered working in a reference to that ship in TBA, but Intellivore established that the ship had never gone beyond the UFP core worlds, so it was incompatible with my intention to take Picard as far away from UFP affairs and territory as possible.
"Hatemonger?" That's a little strong.
However, it is a uniquely negative statement coming from Picard. Typically, it would be Riker's role to condemn the Ferengi or the Talarians, or Worf's role to remind us that the only good Romulan is a dead one, and Picard's role to let such racist statements pass without dignifying them with a response, or even throw a disapproving glance at his colleagues.
Again, I disagree that it's negative, merely cautionary. Plus you're defining the characters in too limited and stereotyped a way. In fact, I profoundly disagree with your characterization of Riker. As a rule, he was the most passionate xenophile, the one who most enjoyed that which was different and alien and was most open to alternative points of view.
Although, for what it's worth, pretty much the scenario you suggest did indeed occur in "The Wounded": After Picard made the statement quoted above, Worf very predictably said, "The Cardassians are without honor. They cannot be trusted." Or words to that effect.