"the unauthorized use or reproduction of another's work."
While I can't claim to know the subtle nuances of copyright law in every country, in the USA if the author distributes their work for free, they have authorized anyone who obtains that work from them to use it. Not to create derivative works, or sell reproductions, or for public exhibition or distribution, but certainly to use it.
By the by, I am twisting nothing, aside from my face into Jackie Chan-like expressions of disbelief at you people who are so brainwashed by the notion that developers are always the victims and consumers are evil incarnate that you cannot process the truth unless it fits that mold.
What happened here is the same thing as if a baker took a plate of bagels out to the street and handed them to people while whispering "stolen bagel," then proceeded to write an open letter which somehow organically finds its way to the papers telling what he had done and complaining that he can't run a business when people keep stealing his bagels, and then laughing at the people who came back to comment that the bagel was rather dry. That twat would be driven out of business, but do it with software and somehow you're automatically in the right?