The way programmers tend to default "engineer" to meaning "software engineer" bothers me sometimes too. On the other hand, I wouldn't be surprised by a mechanical engineering blog doing the same thing. We all focus on our little corners of the world, and if software has it worse than mechanical it's just because mechanical engineers are forced to work with other disciplines more often. I'm pretty sure I've seen over- and under- engineers in mechanical work too, it's the same all over.
For whatever it's worth re: "engineering discipline", my feeling is that the parts of software engineering that really need to take their work very seriously mostly do. For example, the occasional articles on the NASA software that went into the space shuttle. On the flip side, if the mechanical engineers I worked with could build/test/release new designs the way software engineers can we would have been as sloppy and more. The reason physical things are more carefully designed is just that the edit/compile/test cycle is so much longer and more expensive, not that one is a "serious engineering discipline" and the other isn't.