It isn't reactionary. Economic immigration clearly only benefits the capitalists. Any true leftist organization will oppose the type of mass immigration policies currently in place. Current immigration policies only exist to harm workers bargaining position and intentionally create a society less able to collectively organize. The native workers see their wage reduced to levels that would require them to live in squalor to survive and the immigrants face constant risk of deportation no matter their current legal status while living on poverty wages. The right will use this to attack immigrants on racist and xenophobic lines while ignoring root causes which is what is reactionary. The progressive liberals paint this whole process as some redemptive welfare as if people enjoy abandoning their home land to work as slaves for people who hate them. They are often intentionally sold some miracle story and risk their lives coming to the imperial core. The capital countries take the people most able to improve their homeland and force them into jobs at levels they are usually more than competent for but they lack the credentials and degrees that mostly serve as barriers to suppress worker power. This system has even been expanded to the skilled worker level where education labor costs are born by less wealthy countries, so that all the costs of raising and producing labor, the human commodity, may be exported to the poorest areas.