They may be fragile but they are also extremely strong compared to a person. Here is a Tesla bot falling and hitting a closed water bottle hard enough to send water spraying. No human would do that as an international action.

https://www.youtube.com/watch?v=0MUaBCoLu8M

Maybe they're not stronger in the absolute, but you never find a human just giving 100% power by accident, we also sense unintended contact, or unexpected material yield and adjust our force. And maybe that's the problem here, robots constantly glitch and just give 100% force to whatever is around them.