This isn’t accurate. This original coiner of the term (Thoreau) used civil to describe the links between civilian population and civil servants (government) and not as a description of the action (as in civility). He did advocate for subcategories of civil disobedience to distinguish between non-violent and violent actions.
Yes it is. Thoreau may have coined the phrase but he didn't invent the concept. Anyway, it is unhelpful to get bogged down with semantics when the understanding of the phrase is long established. Lots of words and phrases change meaning over time (font for typeface) and we generally take the most understood meaning, especially if it is long established.
Britannica: “civil disobedience, also called
passive resistance, the refusal to obey the demands or commands of a government or occupying power, without resorting to violence”
Stanford Encyclopaedia of Philosophy: “On the most widely accepted account, civil disobedience is a public, non-violent and conscientious breach of law undertaken with the aim of bringing about a change in laws or government policies (Rawls 1999, 320). On this account, people who engage in civil disobedience operate at the boundary of fidelity to law, have general respect for their regime, and are willing to accept the legal consequences of their actions, as evidence of their fidelity to the rule of law. Civil disobedience, given its place at the boundary of fidelity to law, is said on this view to fall between legal protest, on the one hand, and conscientious refusal, uncivil disobedience, militant protest, organized forcible resistance, and revolutionary action, on the other hand.”
Cambridge Dictionary: the act by a group of people of refusing to obey the laws or pay taxes, as a peaceful way of expressing their disapproval of those laws or taxes and in order to persuade the government to change them.