Let someone call themselves whatever they want. If they can do the job they were hired for then... who cares?
I think there's not a ton of political palatability for realizing most of their projects are like one API and a sane use of some SQL away.
But none of that is relevant to my point, which is largely linguistic. If a person is doing a thing, then they are "a person who is doing the thing."
If a person is engineering, then they're an engineer by definition. That's not saying they're a good or bad engineer, just that's what they're doing.
There is a role for certifications, of course! But those certifications are intended to mark a lower boundary of ability, nothing more. Rather than overloading "engineer" to indicate that a person has a certification, I'd advocate calling them something like a "certified engineer". That would be correct and accurate, and wouldn't exclude a whole lot of great defacto engineers.