In the world of agave spirits, desgarradora means mechanical shredder. They can vary in size from small wood chippers to large industrial shredders that tear agave into small chips. This type of milling is permitted for both mezcal and mezcal artesanal under NOM 70.
Here is a video of one in action.
The dictionary translation is “heartbreaking.” When applied to agave, it is quite literal as the desgarradora is breaking apart the “heart” of the agave.