I believe I understand where you are coming from. However, that's not entirely fair. Most jobs have "no legal certification process", but that doesn't make their job title meaningless. Not everyone who wants to define what a title means is doing so to gain or assign clout, many just want to understand what a person with that title typically does.
Granted, there are some titles (especially in technical roles, in some companies), that tell nothing more than "that person works in I. T." (or whatever your company calls it). For example, I've seen roles called "Systems Analyst", that varied greatly in responsibility -- some where all the person did was code all day, some where the person almost never wrote any code. Sometimes that was two people in the same group at the same company.
So yes, titles can hold only a very small amount of meaning, at times, but that doesn't make them entirely meaningless.