I don't doubt that in this case it's both silly and unacceptable that their driver was having this catastrophic failure, and it was probably caused by systemic failure at the company, likely driven by hubris and/or cost-cutting measures.

Although I wouldn't take it as a given that the system should be allowed to continue if the anti-virus doesn't load properly more generally.

For an enterprise business system, it's entirely plausible that if a crucial anti-virus driver can't load properly then the system itself may be compromised by malware, or at the very least the system may be unacceptably vulnerable to malware if it's allowed to finish booting. At that point the risk of harm that may come from allowing the system to continue booting could outweigh the cost of demanding manual intervention.

In this specific case, given the scale and fallout of the failure, it probably would've been preferable to let the system continue booting to a point where it could receive a new update, but all I'm saying is that I'm not surprised more generally that an OS just goes ahead and treats an anti-virus driver failure at BSOD worthy.