Ha! I probably shouldn't take your obvious troll bait seriously, but I'm a sucker. Maybe you should click the OSS projects link in my signature? I'm the author of libgdx upon which Spine is built. I give away libgdx, Kryo, and many other projects for free. I also maintain and support users of my projects for free. People who write OSS know what they are doing when they choose a license that allows others to profit for their work. Who are you to judge people who would follow the author's licensing to profit? There is nothing wrong with wanting to be paid for my efforts. Software engineers need to eat too.

the two above are of course the main contributors, but the projects has as many other open source projects lots of authors. I also contributed some lines to it(like 5 or so)