The thing is that it's perfectly possible to achieve maximum scores in both English and French. Without any of them having to be your actual first language. For the purposes of an EE profile, you have to choose one of these languages as your first (whether that is true in real life or not). This is why it makes sense to request certain test scores, without insisting that it has to be your first language.Lol
Unfortunately, OINP doesn’t give out as much information as one may want only if you contact them. From the commencement of the French stream they made mention of french as first language in their letter to IRCC so I don’t know why they wish not to continue mentioning that.
I don't know what the OINP mentioned when it first started, I only know what it says now.