I learned RUP before Agile, and didn't hate it. I only learned if you like one thing you necessarily have to hate something else later in life. Aspects of RUP make it into my interpretation of agile. For example, I teach my dev teams UML (sketching as defined in Fowler's book) for whiteboarding and the rare BDUF, which RUP exposed me to. Speaking of BDUF, I've saved many a feature by resorting to BDUF when communication broken down.
I didn't and don't want to start a flame war, but needless to say once in an interview I was asked if I was a "Scrum Master" (after having about 15 years of agile experience). When I stopped laughing, I said, "No, no I am not." I don't think they got the joke, and no - I didn't get the job.
I don't think "iteration" vs "sprint" is a minor quibble. I've seen the "wrong mindset" you speak of, as people take "sprints" far too literally. It's not a sprint, it's a jog. A long, long jog. You'll be stopping for water and stretching along the way. Sprinting is a good way to pull a muscle and have all your devs quit on your one day, leaving you with a big-old case of backlog rhabdomyolysis. I took that analogy way too far.