Let's call a spade a spade. The reason this country is 'stopping the boats' is not to stop drownings at sea. You stop drownings at sea by rescuing people. You are not 'saving lives' by turning back the boats, you are sending people back to places where they will die anyway. By stopping people fleeing any way they can, you are simply working for their oppressors.
The reason this country turns back boats is because, at a political level, it doesn't think there are votes in accepting refugees.
Conventions and obligations asides, the simple fact is that the people in power are afraid to accept refugees in any significant number, because it will. not. win. votes.
So let's start a different conversation. We will never develop a truly humanitarian policy by talking about what we SHOULD do, or what we are OBLIGED to do. So let's start a different conversation.
Here's one. What can refugees do for us? If we start looking at the question looking for the benefits, there are many. For a start, it costs tens of thousands to educate and raise children up to the age when they can begin contributing to society. Here is an entire wealth of people who could, with the right support, start working. There are the trained professionals, who are refugees from war, famine, or oppression. There are the men and women who are not afraid of hard work. Why not start a conversation about what benefits there could be from opening our country to people in need?
For another, our population is ageing rapidly. In 40 years, there will be fewer than 3 people working for every pensioner. This is not sustainable.
I don't like these conversations. I don't think we should HAVE to look for benefits to us. But the other way isn't working. Appealing to humanity isn't a strong enough argument to sway those in power. So let's appeal to whatever else might sway them.
Let's start a different conversation.