I and everyone I know are severely underpaid, or this site is a bit wrong.
I'm with you. At Thales (big french tech company), AFAIU there's essentially no way of reaching 60kEUR/year without becoming a manager. And even then, reaching 100K requires climbing a lot more levels.
You're probably thinking of after-tax salary, also known as take-home pay (5k/month in your example).
Salary is almost always discussed in pre-tax terms, because two employees with the same salary can get very different tax deductions based on their family situation etc. This website is no exception, as far as I can see.
(Of course, this makes sense when comparing within the same country. When comparing different countries, tax rates are already different before you consider discounts.)