"Remoaners must be getting worried. They have added death threats to their arsenal. Nice People!???????????"

Several things. It isn't "they." It was one person. Shall I helpfully redraft your sentence for you?

"In isolated cases remainers are resorting to tactics such as death threats, in a single case that we know of targeting an 80-year-old. There is, clearly, no evidence that this is anything other than the work of a criminal mind and does not in any way represent the general demeanour of remainers, any more than the mindset of the Yorkshire Ripper represented the mindset of British men in general."

I think that you should also include the rather unpleasant Zac Goldsmith and the editor of the Daily Mail in your "nice people" characterisation...