The world hasn't ended, but I'd argue that the number of malicious actors within the space is rising, as are the consequences of being compromised. We're simply seeing more and more malware make its way into open source ecosystems, and I don't imagine the trend will be reversing. For this reason alone we should be striving to achieve full build reproducibility, though I agree with you that demonizing (or threatening) Dtolnay is wildly inappropriate.