edit: Point is that its just branding, there's nothing to get. If you think that its funny/clever/whatever, wait until you hear the the company Apple made a computer and called it a Macintosh. Because macintosh is a type of apple. apple, macintosh, nobody gets it seriously?
Also, valves don't make steam. The flow of steam is controlled by valves in whatever machine still runs on steam, which is the actual "joke".