How I discovered it:

Upon seeing the new nether snapshot mob, the strider, I decided to do some tests with different potion effects. Out of curiosity, I threw a splash potion of slow falling at a strider, mounted it, and guided it off a cliff. To my surprise, both I and the strider splattered on the ground, unaffected by the effect. I also tried the same test with pigs and horses and got the same result.

The real question:

Is this intentional design, or simply an overlooked bug? Thank you for your time and consideration.