The issues wasn’t that they used human contractors to improve the speech recognition technology, but the fact that Microsoft didn’t explicitly stated that in their privacy documents.
Human contractors will continue to listen to your Skype calls
As a result, the company updated the privacy policies and support pages of both Skype and Cortana:
When you use Skype’s translation features, Skype collects and uses your conversation to help improve Microsoft products and services. To help the translation and speech recognition technology learn and grow, sentences and automatic transcripts are analyzed and any corrections are entered into our system, to build more performant services. This may include transcription of audio recordings by Microsoft employees and vendors, subject to procedures designed to protect users’ privacy, including taking steps to de-identify data, requiring non-disclosure agreements with vendors and their employees, and requiring that vendors meet the high privacy standards set out in European law and elsewhere.
Despite not being the only company that does this, Microsoft said that they won’t stop using this technology.
Keep in mind that voice conversations are only recorded when translation features are selected by a user, so you don’t have to worry about all your conversations being recorded and reviewed by human contractors.