Magento code in general is of very dubious quality. I once ran a quick static analysis on it and found some ridiculous results: https://twitter.com/jlas_/status/391615992473722880
Granted, the tool I used is opinionated and not all those items are red flags, but the sheer number of issues is impressive.
If you wanted to call them out, at least call them out for something which actually runs during normal operation.
Every book I've ever seen on Magento seems to think the same. That 777 permissions are just not a big deal.
"All directories have 700 permissions (drwx------). 700 permissions give full control (that is, read/write/execute) to the owner and no permissions to anyone else.
"All files have 600 permissions (-rw-------)."