How so? We understand what it means to be hanged. It's historically been a widely used execution method not strictly tied to English speaking countries. It's cheap to set up, does the job, and is easy to just display for a little while, after all. And it's also still a popular suicide method.

The confusion in the title comes more from the ambiguity in "'Labor". It's not immediately obvious that Labor refers to a political party rather than just the word. It's also not immediately obvious that the "by Liberals" bit does not mean "Labor" is something made by Liberals.