Sure, maybe the one month in the year when they fly 120 block hours and 80 sectors, a TRI/TRE make that money, gross. Maybe.
Then there is the small problem called taxes and social security, which the majority of the western pilots in wizz happily decide to ignore. Until the taxman comes knocking at their nice house in London or Germany.
10000 is certainly not representative of the average monthly pay, and anybody saying otherwise is wrong.
Ask them to show you the payslip.
And before you ask, I worked there, so I know more than a few people, and I know the contracts offered, with all the tricks involved.