[brippalcharrid]

Countries are defined by their borders, and governments are perfectly justified in using force to control access to their territory. The fact that there is a pathological unwillingness in some industries to comply with immigration law (in collaboration with some politicians and administrators) and a willingness to externalise the costs of their "cheap" labor might have given you the impression that this state of affairs was inevitable or necessary, but it is just a mechanism for corrupt businessmen and opportunistic politicians to gain monetary and political advantage at the expense of citizens, as well as technological progress (an endless supply of unskilled and semi-skilled labor below the market rate removes the incentive to invest and innovate). Factors like birthright citizenship and chain migration further exacerbate these problems.