From what I can tell, that's simply saying income from taxing migrants is greater than the sum of benefits given to migrants. It goes on to validate the point it is making by showing migrants to be more valuable (in terms of net tax income per capita) than the native population. I don't dispute that, but it isn't the point I'm making - I'm talking about the cost that total net migration has on all infrastructure, not just benefits.
Here is the graph of migration to and from the UK by year:
It wouldn't be unreasonable to suggest that at the current levels and rate of growth, we should expect net immigration of 350k this year.To accommodate that without impairing current services, we would need to build a city the size of Leicester. And carry on doing that every year that migration is at this level. Where would you put this year's Leicester?
Average UK household size is 2.3 people, so we would need to build over 150k houses. Using Leicester as a guide, they would also need 3 general hospitals, around 17 secondary and 75 primary state schools, around 15 doctors surgeries, a train station and more. Not to mention the staff that all of them would require.
The alternative is to bung them into existing houses/services and you see the facilities stretched to breaking point like we have now.
Please note, I'm not anti-migration. Half of the team I work in are from all over the world. I'm just against immigration where we don't need it. Another factor that your link didn't consider was immigrants undercutting native workers and leaving them unemployed. I don't think it's wrong that people have a standard of living threshold that doesn't force them into living 7 or 8 in a house with several sharing bedrooms.
Nor is immigration by any means the only reason why I'm against the EU. Nobody has ever voted for anything about the EU - our membership, those in charge, what it's meant for, its budget, etc. - and I can't abide such a bloated undemocratic drain. TTIP's farcical as well.