What do we mean by this term?
Rhetoric refers to a speaker or writer's ability to persuade or motivate a group.
From the political rantings at Speaker's Corner, Marble Arch, to the speeches made by politicians we see examples of 'rhetoric'.
The ancient Greeks used rhetoric in many varied forms via public orations and a good exponent of the art was virtually gifted with a meal ticket to gain admittance to lavish 'dinners' on the strength of his/her powers of rhetoric.
Debating often employs rhetoric and 'The Oxford Union' has a long history of hosting international figures and celebrities. Competitive debating on a world-wide scale is common.
Democracy and freedom of speech are surely a prerequisite and repressive regimes most likely would strive to prevent it.
A rhetorical question is a question that you ask without expecting an answer. The question might be one that does not have an answer. It might also be one that has an obvious answer but you have asked the question to make a point, to persuade or for literary effect.