I’ve become aware of the inexplicable use of the phrase “not unsurprising” in contexts in which a simple “unsurprising” is called for. For example:
Unpresidential, But Not Unsurprising
It’s extremely unfortunate yet not unsurprising that such an attack occurred.
Annoying but not unsurprising.
In each of these examples, the sense is that something might have been expected and is therefore not surprising. Placing “not” in front of “unsurprising” garbles the meaning.
Something is either surprising or not surprising.
surprising: adj. Causing surprise or wonder by its unexpectedness
The word unsurprising may be used instead of the phrase “not surprising.” The OED doesn’t bother to define unsurprising as “not causing surprise,” but it gives this illustration of its use:
Adaptations of Dickens’s works..are meant to make you feel good. This is unsurprising, as..it could be argued that this is exactly how Dickens intends you to feel.