All because the law is based on geography. As soon as they're on EU soil, they have the same *essential* rights as any EU citizen. (Essential meaning: the right to live, be fed, be taken care of the h...
Forgot to mention: education, and the right to be with the family (i.e. we pay to have them fly in from their shithole and pay them child support, and of course they can then also pull in their family, so we often end up with clans, which can become criminal and "untouchable" due to their size and brutality.
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