What makes you think that if the immigrants were legal they would not work as hard and leech the social system unlike the natives?
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>Leechers exist among natives too. Any particular reason to believe that it’s worse with the immigrants?
No in fact I've stated the opposite. The incentive structure for immigrants self selects the illegal ones as ones willing to work without social support, because it isn't offered to them. The legal immigrants, unless sponsored by family/spouse, generally have high education or wealth requirements than our average populace thus they're less likely to use benefits.
In fact I think my country could look at the incentive structure that has made the illegal immigrant in my country so hard working, and think about how we can apply to making our own citizenry more independent and less dependent on public benefits.
In attempt to tackle the economic crisis that the Turkey is in, last December the Turkish government introduced a banking instrument indexed to one of the USD/EUR/GBP currencies where you can put your Turkish lira and earn interest of up to %17 but if the Turkish lira loses more value than your currency of choice the government will match the difference. So at the best case you earn up to %17 interest and on worst case you don't lose in terms of foreign currency.
Anyway, they made it available to foreigners too in attempt to have the Turkish diaspora in Europe and UK bring their money to Turkey. Unfortunately it failed to fetch any significant demand and BBC Turkish made a small documentary with the Turks living in the UK and talked with them on why they did not took the opportunity.
The answers were actually shocking: Turks were working illegally so that they don't pay income tax and receive state benefits and as a result they couldn't put their money in the banking system because Turkey started sharing data with EU and UK. It turns out, there are many Turks who are officially unemployed but are actually working illegally and not paying taxes.
I don't deny the existence of leeches, I wish they were caught. EU made a significant progress with the Turkish cheaters and their money is no longer in heaven in Turkey.
I don't think any country needs to give the right for anyone to come there if they want.