To me, it's a fairly myopic culture. One of my friends, who has a Ph.D. in civil engineering and is a professor at Stanford has to do the same thing "oh no I'm not an engineer in the way you meant". It's insulting to all the other types of engineers out there (civil, mechanical, electrical, aeronautical, bme) who are somehow excluded from the definition engineer when you enter the Valley or software circles. No other engineering subtype abuses the language this way. It's even more mind boggling because no software engineer has a PE, which in some countries (not the US) is the only way you can call yourself an engineer.
As a whole, I think abusing the language is insulting to the diversity of engineers out there. While software engineering is probably the highest growth branch, that doesn't mean the other branches are just as relevant. In university, we never used the word engineering to mean just "electrical engineering", we actually used it when we were talking about the whole universe of engineers.
The funny thing is now that I've transitioned to software engineer, it feels good to be finally be able to say "Yes I'm an engineer."