Why do we need retractable gear to get our commercial rating?

[JasonM]

I don't understand why this is a requirement. What if I wanted to fly a standard 182, 206, 208 or a Sea plane commercially and never had intentions of flying or owning a retract. Seems like it should be possible with some type of restriction to fixed gear.

 

[Jim Logajan]

Seaplane Commercial (C-SES or MES) requires no retract gear.

Also no retractable gear training time requirement for commercial helicopter, gyroplane, powered lift(!), glider, airship, or balloon. As far as I can tell by a quick scan of 61.129.