Okay, fair enough. The thing is, we're living in a non-ideal world and so have to deal with the reality of immigration. Immigration is a fact of life. Without it no Western country would exist in its current state - i.e. without having raped and pillaged dozens of countries of their riches and their people (to work as slaves here, there and everywhere, actually building the country with their bare hands) we today would be a lot poorer than we are.
As well as that, without immigration, the entire world population outside Africa would simply not exist. Not at all. You would not be here. I would - well, I might, depending on what's in my family tree, but you certainly wouldn't.
So immigration is a hugely complex issue, and if we ignore the wider context we cannot find a realistic or workable solution.
I do agree with you that there are many examples of immigrants claiming benefits, etc, and not working - even an immigrant friend told me about this. I don't know enough detail to be able to give specifics about the way the system works, but I agree that at the moment it is seriously flawed with regard to immigrants.