As the strongest OS advocate who has not ran Windows in a quarter century and is posting this over a Wireguard link; the is some double standards here. A corporate VPN vender who did not ensure they received all notifications from Microsoft regarding a certificate that effectively let's them root millions of computers would be a strong signal of concern.
It goes both ways. Probably both parties are partially to blame here. But it is clear that this corporation did not provide a sensible support channel for such an important project to resolve the situation quickly.