Spending 50% of your income on rent isn't the same thing as losing money, unless you're defining "losing" to mean "spending." I doubt many of these SF tech workers started with some savings and are watching their savings decrease each month.

No, the context is insane rent prices. That doesn't translate to losing money. Several people have stated that the difference in salary is making up for it, to where they have as much after rent, after tax income or more than in other places.