No, they have a massive sales team, they just call them "customer advocates" or "Ecosystem Account Manager" or "Product Advocate"
https://www.atlassian.com/company/careers/all-jobs?team=Mark...
https://www.atlassian.com/company/careers/all-jobs?team=Mark...
edit: To be fair to the author that wrote the article, he nearly immediately called out that Atlassian simply had a lower-than-normal amount of money spent on sales and marketing, and made no claim that they didn't have a sales team. I suspect he didn't write the hyperbolic headline -- blame his editor.