Earlier quoted context omitted.
> By even flagging the issue and the potential fallout, I’ve put my career at risk. Simple as. Not your company? not your problem? Notify, move on.
Their websites says they're a freelance cloud architect. The article doesn't say exactly, but if they used their company e-mail account to send the e-mail it's difficult to argue it wasn't related to their business. They also put "I am offering" language in their e-mail which I'm sure triggered the lawyers into interpreting this a different way. Not a choice of words I would recommend using in a case like this.
[1] We get about as many 'pay us a bounty or we'll tell the world about this horrid vulnerability we found'. I have suggested to legal we treat those like extortion attempts to make them go away and stop wasting our time but legal doesn't want to spend time on it.