This is really just a rant about how poorly PuTTY is distributed. (and a vague implication that it is malware of some sort). I think it is a valid criticism, and I wish the person who wrote PuTTy (an SSH client for windows) would be more open/available/transparent but it is hard to force that on someone.
Everyone who distributes exe files should include some form of authentication otherwise you are just sloppy. In all likelihood he doesn't check authenticity of software on his end so you can imagine other risks as well.