Yes, I consider myself as one (to the point of course). I tried to ride my 2 horses 4-5 times/week, and that's plenty of exercise. I could tell the difference in my core muscles, legs, etc. when I started working seriously.
However I don't consider those taking lessons once/week or going for pleasure trail ride 1-2 times/week as athletes really.
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."