Who comes up with an argument for considering nulls distinct??

Imagine a programming language where `if (variable == null)` always returned `false` because nulls were considered distinct. What kind of reasoning goes into thinking that's a great idea?

> If nulls are considered distinct, then having more than one of them won’t cause a unique constraint violation.

Gosh, I would've thought the spec was fine as it was, having to spell out that the DB should consider two null values equivalent for UNIQUENES constraints is like spelling out that "two integers that have the same mathematical value should be considered equivalent". I guess they need to add that in the spec if it's missing as well.