What's wrong with the left's argument on immigration?

This is a very quick post (I have lots of work to do and shouldn't be blogging at all).  But today the Prime Minister is set to make a 'big speech' on social housing and immigration.  This has led to some interesting discussions on Twitter about how the left should tackle the immigration debate (similar, really, to debates about welfare).

In general, I think the left uses two arguments to try and change views about immigration:

1. Immigrants make a strong economic contribution to the UK.
2. Fears about immigration are based upon myths.

As the current state of the immigration debate testifies, this strategy is failing.  Largely, I think it fails because a) it adopts a purely rational approach to a sensitive, emotionally charged moral issue and b) it paints people's concerns as being led by a belief in myths.  

Alternatively, I think the left should use three different arguments to support immigration:

1. We should be proud that immigrants from around the world want to come to the UK for a better life (the moral argument)
2. And we will strongly support and invest in policies that promote the integration of immigrants (the inclusion argument)
3. However, we recognise past immigration has brought about great changes for certain communities.  Where we have immigration, we will manage it well (the management argument)

Adopting these arguments would kill two birds with one stone.  First, it would make a moral case for immigration - rather than a cold economic one.  Second, it would recognise people's concerns as genuine; something the left, too often, just doesn't do.