There are 2 kinds of debates, those involving differences in reasoning, and those involving difference in basic principles. You can the former, but almost never the latter. People don't negotiate on core values.
This is why discussions regarding immigration involve so much passion..
There are two views of immigration, and they are irreconcilable.
The first view sees immigration as a social issue to be addressed by the country in a manner that best suits the perceived self interest of the nation. ("best suits the perceived self interest of the nation" still includes a LARGE area of dispute).
The second view sees immigration, particularly immigration involving people looking to improve their basic standard of living, as a basic human right, and that most restriction (keeping out war criminals and pedophiles is OK) is an affront to basic human rights.
These views are irresolvable, and there cannot be a meaningful debate.
Abortion is analogous. If you believe that it is the murder of a human being, you cannot negotiate, or have meaningful debate, with those who see it as an issue of privacy and choice.