It's more nuanced than article or commenters on HN want it to be. If there's a constant communication channel between companies and there's a reason to believe that patch can't be created in 90 days, sticking to deadlines seems to prioritize the wrong things.

On the other hand if MS wasn't responsive enough and upfront about the time it'd take to patch and reasons for that, then sure, 90 days seems more than needed leeway for Microsoft. But I don't know how things worked and I've seen enough to assume that both scenarios are possible.