You missed the point of the quote - it's diversity between social groups, not between race. It's likely that all the employees in the tech sector are of a simil

You missed the point of the quote - it's diversity between social groups, not between race. It's likely that all the employees in the tech sector are of a similar earning potential, a similar age, and have similar upbringings and home lives. This contrasts with the rest of the people living in the area, and causes problems.