The best I can tell is that the big difference in perception comes from people who worked on code for manned flights or anything that will interact with an actual human being vs non-manned and even non-mission critical code.
It seems that anything that will come close to a human is developed like it's the new arc of the covenant while for anything else it's YMMV based on the project and the team.
The amount of process and oversight is highest at class A, and lowest at class E. If you are developing class E, you can do pretty much whatever you want and your team doesn't even need any training in software engineering.
If you want some fun, track down somebody working at the NASA Enterprise Applications Competency Center and ask them about the Office of Education software. (Me, I know nothing, through an exercise of good luck and skill. "No hablo ingles. Tengo hambre. Mucho muerte. <feigns death>")
(I have a friend and excoworker there who was an aerospace engineer, specifically concerning the design of solid rocket motors, who explained why Constellation was not going to match its hype: you can't add a segment to a SSRB to get a bigger motor; it's a complete redesign anyway.)