> You must either think theft when needed to preserve life is morally justified or not.
If I must take a binary position, then yes. Theft when needed to preserve life is morally justified. In fact, it happens every day on a massive scale. Governments around the world seize up to half of what their citizens earn and redistribute it according to the needs of the whole, for example in order to save lives or support those who cannot support themselves for any of a number of reasons. I support the argument that taxation is theft, but not that it is wrong.
> If you want to argue that IP is not real ownership and should not exist [...]
I don't want to argue that IP is not real ownership. I want to argue that there is no such thing as real ownership, whether the property in question is physical or intellectual. Practical ownership is only what can be enforced through the monopolization of violence. Governments have the power to assert ownership of their citizens' earnings, but for the most part choose to allow citizens the privilege of keeping a portion of those earnings and pretend that they own the goods and services those earnings pay for.
This discussion has strayed quite a bit from the initial question of whether or not piracy = theft = bad. By challenging the reality of ownership, I'm trying to challenge the assertion that piracy is inherently bad because it infringes on ownership and ownership is a fundamental quality of the universe that cannot be rightly infringed upon.
That we choose to adopt certain principles, such as that of ownership, and act as if those principles are "true" in order to make sense of the world, is a perfectly legitimate practice, and I don't believe that you are wrong to do so.