We are pushing this because it is a Rotary, and that's just how you measure Rotaries, always have, always will. If you actually owned a Rotary car, you would understand this argument better. If you want to measure it like a piston engine for some weird-ass reason, it's a 2.6L, and if you want to measure it by total volume, it's a 3.9L. The fact still stands that you measure a Rotary by displacement through one rotation of the eccentric shaft, because Rotaries don't suffer from the inherent weakness of a piston engine; the need to spin twice to make one power stroke in every cylinder. If you came across a 1.3L two stroke piston engine, would you accuse it of being a 2.6L? I think not.

And yes, the Rotary IS a four stroke engine... it just does it better then others.

If you really want to measure an apple in terms of oranges, go right ahead, just don't try to convince others that this apple IS, in fact, an orange.