I'm not sure I understand. The only way you infused your black spindle is if you had the vendor version- the drop was already at max light so you wouldn't have infused it. Patching just the kiosk version then would only impact the people that had a black spindle that could have been infused and, chances are, if you bought a black spindle from the vendor at all to keep for its own sake and not to infuse, you knew the news. Why else would you?
Also,I find it strange you frame the 2 week delay as something that would "mess" with the communication rather than what it is- as big a lead time as Bungie could give. We're blaming them because they put the word out as far out in advance as possible? This feels like a damned if you do, damned if you don't situation. I do think a final heads up notifying us that this is the day would have been nice, though. (assuming last week's update didn't have that)
Lastly, I seriously doubt it's even technically possible to selectively identify which spindles originated from the kiosk and which dropped after the fact. Granted, I'm obviously not a Bungie engineer, so this could be pure bs.