NEW YORK CITY — With a long day full of career milestones waiting, the zaniest member of the 2018 NBA Draft class exited a luxury hotel in midtown, pausing midway through a dissertation on the ethics of aquatic park dolphin shows to accommodate a cluster of autograph seekers. “It’s fake positivity,” Lonnie Walker IV declared. “How would a human feel if they’re just locked up in a small place where they have to stay for the rest of their lives? The dolphins are doing the same thing over and over. It’s like prison for something they didn’t even do.