Answer:
Because immigration is a natural process and a policy of open immigration avoid many of the problems, costs and negatives effects of illegal immigration.
Explanation:
In a country with open immigration people will not use of fraud to get inside the country or to get work, that way the state doesn’t need to spend so much money in securing borders or investigating frauds and illegal workers.
With open immigration the immigrants are able to participate in the economy and pay taxes as other citizens, these increase the states income and the opportunity for investors, if they are illegal they can’t open a legal business, as happened in past with the Chinese’s for many years in US. Or they won’t need social welfare because they can have an income, that way they don’t have to be under the state’s support or be in custody in prisons.
They can also respond to law and have some responsibilities as other citizens without having all the native’s rights, this creates a more equal situation than when they are illegally immigrating.
