Because there still are many broken CPUs out in the wild. Firefox works around the crash so the broken CPUs won't flood the channel with crash reports.

For example:

Does he mean all existing 13th/14th gen CPUs (prior to Intel's discovery of the vmin issue) are broken in the sense that they are susceptible to damage and can only be replaced.

OR

Does he mean that the microcode updates, applied by Intel to existing CPUs that are susceptible to damage, will only slow degradation and the CPUs will eventually fail and can only be replaced.

OR

Is he saying the 13th/14th gen CPUs which have already sustained damage, cannot be fixed by microcode updates.