Why didn't anyone think of this as a torture method?

YmSelf said in comment #2575655:

Why didn't anyone think of this as a torture method?

Because it's not that simple.
Oripathy lesions like this goes DEEP beyond skin; they're product of your cells dying and fusing into rock, so it can be anywhere from 'muscles fusing into stone' or 'growth from bone jutting out of skin' levels of body horror and not just 'some crust on your skin' like this.

But Yelena (Frostnova) apparently does this voluntarily, albeit quite in different way (breaking off spikes of originium growth and giving shards of it as 'lucky charm' for Yeti units.)