>>513369276 (OP)
Because there's no way to oppose immigration without belief in natural hierarchy and the value of the past. Whether it's a racial hierarchy, IQ hierarchy, cultural hierarchy, language differences, etc... anything that imposes a standard to separate populations and restrict the "free movement of labor" is because you believe that there is something in your country that it has by nature which makes it preferable to that of others and you want to preserve those characteristics. Leftism says that all identity and characteristics are infinitely malleable and it's bad to resist change. According to leftism, nature is in fact evil because you didn't choose your nature and therefore because nature isn't freely chosen nature is oppression and the goal of humanity is to dominate nature and surpass nature via "progress."
Limits to immigration would limit the rate at which we can transform society and thus all any form of opposition to immigration is opposition to "progress" because all humans have a right to live in the most progressive society on Earth and because the purpose and goal for all human society is progress.
All immigration restriction is based on preservation rather than progress and thus is EVIL because the PAST is something to be hated and surpassed NOT revered.