[mavelikara]

As sibling comment explains, this is a natural outcome.

Interviews are a poor proxy for predicting on-the-job performance. The manager is disproportionately affected by poor performance of an employee. So, they try to minimize it. To do that, they try to get signals outside of the traditional interviews. And one such extra signal is reputation. Seeking candidates with high reputation leads to developers with open source contributions getting hired, but also those from the manager’s personal network get hired too.

This effect is not limited to immigrant managers.