I think I would agree in other cases but in this case it is likely it was a phishing attack in which OpenSea were impersonated to steal user signatures. I think

I think I would agree in other cases but in this case it is likely it was a phishing attack in which OpenSea were impersonated to steal user signatures. I think if someone held a gun to a crypto owner's head and forced them to hand over their seed phrase then that should still be called theft. Entirely different scale but still an "involuntary transfer" within the code's "law".