Mott actually served a purpose. "He's the best barber in Starfleet". WTF can Neelix say that compares to that? I figure that gives him a little leeway to chat up the crew, especially since it only happens when they're in his chair, and the only time we ever saw it was with Picard & Worf who are likely the 2 most antisocial people on the whole damn ship, & therefore must make for an awkward social exchange in that setting. Who could blame him for trying to ease the tension?
Alternatively, Neelix is the JarJar Binks of Star Trek