"Forgive them, for they do not know what they are doing." Not being a Christian, I still thought this was pretty accurate. Of course, I can only guess what it feels like to be in the situation you are in, dear Teal. But being an avid follower of your teachings, these are my thoughts and observations of your situation: the fact that you actually took the time to compare the two books to prove that you did not plagiarize looks to me like you are in a state of justification, trying to prove to "them" that you are right and they are wrong. From their perspective however, they are right and you are wrong. Trying to change their perspective by means of logical argumentation, without them actually wanting to change, will be futile - if they cannot prove you wrong here, they will find other arguments and they will make other videos against you. Since you cannot change them, you can only change yourself, your perspective.
Instead of resisting your haters by trying to prove something that you do not need to prove (since there is nothing to prove), why not allow them to be? They are ego-driven, so they are suffering, maybe without even knowing it. One should have compassion for them, for they are not aware that their hate is driven by their ego. Allow them to hate, and do not resist them. I know this is easier said than done, since I am not walking in your shoes, so forgive me if I seem insensitive. To quote Eckart Tolle: "If you are not in the state of either acceptance, enjoyment, or enthusiasm, look closely and you will find that you are creating suffering for yourself and others." If you manage to come to a place of accepting your haters, your suffering will end.
With much love,