Why pick on Heroku for this? Google, Microsoft, Apple, Facebook, and basically every other tech company do the same thing.
Of course, this gets severely down-voted because many people on HN and similar sites think of themselves in this fashion, and their ego takes a hit when they run across a comment such as mine.
To me "engineer" evoques a specific methodology and state of mind that is shared by all engineers, whether they build bridges, sewer systems or software. It emphasizes that your job is to create solutions to real-world problems - and that writing software is just one part of that job.