“unless the reduced speed is necessary for safe operation”

If somehow you got a ticket for this, you’d just say it was necessary for safe operation, after all, why else would there be a speed limit in the first place?

The legal explanation clearly states it is applicable to highways only. I'm sure 25mph / 40kmh is not the intended way of driving there.

So yeah, I still don't believe you that I'd be fined for driving 25mph in an area, where 25mph is the speed limit.