Title of a literary piece sometimes carries the name of a character, sometimes the name of a thing, again sometimes symbolic of some greater meaning. The poem ‘The Inchcape Rock’ has taken as its title the name of the legendary rock which is the centre of all the events. The rock had caused a lot of shipwrecks previously. Then the good Abbott tied a bell to that to warn the passing ships of the danger of the rock. Later the villainous Ralph cut the bell from the rock to help his own cause of looting the ships in danger of the rock. And in the end, the villain gets punished when his own ship hits the Inchcape rock and he dies. So we see, the entire story revolves around the Inchcape rock. So, it couldn’t have a better name straightforwardly suggesting what’s the story is all about. That is why the title of the poem is just and apt.

[Note: While writing an answer about the appropriateness of a title, in most cases you have to find ways to prove that the title is just. Even though you might find titles that would have been better, you should try to show the existing title appropriate. That’s what you are supposed to do.]