Is that due to software engineers or management/marketing? I doubt that engineers could make such decision
I'd go one step deeper. Where did they learn to say this? I bet they learned to say this from the business.
Because I've asked about input validation on a line of business application and heard something similar to this "given this application is used by internal users only and because these users are trained experts on this subject, we don't need input validation".
You will get shut down really quickly if you ask whether a combination of choosing option A in step 12 and option C in step 37 together makes any sense at that company. Ask me how I know.
Oh yeah, of course the same person asked why we allowed these combinations once the application hit production.