Macet watched all those people die and couldn't save them...I wouldn't necessarily characterize his words as a rant, because I do think they were based on reason as well as emotion--but there's absolutely no doubt that what happened to those people haunted him. And while he felt that he stood a good chance of being able to work with Starfleet officers on his turf, it definitely brought his old wounds back to the surface.
To me, what Picard was wasn't soft-hearted. It takes a lot of hard-heartedness to watch people die for your interpretation of a law. I think that he was a politician.
I do agree that the character really changed during the movie era, and very much for the better. First Generations made him realize he wasn't invulnerable, and then First Contact made him look at the ugliest side of his own nature right in the face. I hate Insurrection, but he DID defy orders and politics. And in Nemesis he was ready to take action. But in "The Wounded," he was dead wrong.