Really? Because being the bottleneck (i.e. single point of failure) responsible for approving all addons is exactly what bureaucrats would want to do ;-)
The non-bureaucratic thing to do, as has been pointed out many times of course, would be to give users the power to override the cert signing check as an advanced option.
It is, in fact, an "advanced option", in about:config.
Second, because we care about solving problems, not being bureaucrats.