I, for one, was a massive fan of FOMA. The number of Brazilians, Colombians, Argentinians, Bolivians, Venezuelans, Chileans, Peruvians etc. that I know wouldn't have been possible without it.
But on a serious note. The argument that immigration is an economic benefit to the country is, clearly true. But, anybody working is a benefit to the economy. People earning and spending money is the economy. But surely if the people "coming in" are working for less, then they are not as beneficial as somebody here doing the job and earning more. If those "coming in" drive down wages overall, then everybody earns, and therefore spends less.
I'm not arguing against immigration, culturally we benefit more than all the money in the world could ever provide (even if they cared to try), I just think that, as usual,, the economic argument is disingenuous.