The article is terrible. What are commenters even discussing without having additional context?

   The hackers initially got access to around 14,000 accounts using previously compromised login credentials, but they then used a feature of 23andMe to gain access to almost half of the company's user base, or about 7 million accounts, the company previously told Business Insider. 

This is the only actual 'information' in the article. The rest is just finger pointing. But what does this mean?

What feature? Does 'gain access' here mean all the data you would have as if you logged in as that user? How does 14K become 7M? Is it that case that an average user has access to the data of 500 other users on website? (7M/14K)