I would say no, a NPE becomes a patent troll when rather than publicizing and trying to license the technology they developed to companies that might find it useful they wait for their developments to be independently invented or unknowingly copied and then sue the infringer. Or they patent a technology used by another group but which hasn't already been patented, and then sue the inventor (which has happened to groups I've been a part of twice).
In general it's hard to come up with useful inventions without a concrete problem, so often good NPEs are in communication with their potential customers even before they start work.
In general it's hard to come up with useful inventions without a concrete problem, so often good NPEs are in communication with their potential customers even before they start work.