Most of the common "Stone Fruits" have substances that are not good for consumption (Including the possible leaching of them into juices) and more importantly can add bitterness or off flavors.
While you probably would never truly get seriously sick from the stones, they are not likely to ADD any desirable flavors to your wine.
For that reason, I'd never put cherries or other fruit stones through a blender. Needless to say those pits also are not going to do your blender blades any favors.
A lot of this sort of thing comes down to folks looking for short cuts or an easy way to do something. In many cases, probably most cases really, things like removing the stones/pits/seeds is done for reasons more than just wives tales of poisons in the things that "have" to be removed. Some things are just going to require a little work to get done right, but; companies like the one who produces "Brewsey"(SP?) are out there willing to 'help' folks looking for the easy way out, regardless of what quality sacrifices might be involved.
I still like the phrase "Sometimes if you want something in the worst way, that's just how you are going to get it.
I'm more than willing to admit that 6 years ago I had hoped that my $50.00 Country Fruit Wine Making kit would provide EVERYTHING I needed to get started. Silly me, several hundred dollars later, practically speaking, I now have pretty much all the hardware needed to make good wine. It's just that labor part will never go away or get REALLY easy, no matter how much money I spend, or how many short cuts I find.