I'm curious, did you let them know that this vulnerability exists before you wrote an article and posted it to HN?

If you let them know and they ignored you, then I understand that you'd want to write an article and spread it around. It's important that customers know when a company doesn't value their security. At that point, the proper way for them to handle it is to quietly fix it, and then let all their affected customers know so they have a chance to change their security settings.

However, if you didn't give them a bit of time first, then you are doing more damage than good to them--and their customers.