Most newspapers have some limits on how often folks are allowed to flood their pages. As a relatively new Delawarean (11 years) I am not fully aware of what your relationship with Don Flood is, other than that he used to write for you on your payroll, I believe.
Perhaps you and he have an agreement that in his dotage he is permitted to write (and you are obligated to print) any old thing he wants to put on paper, as often as he can make paper and pen meet. OK. Can you publish what that agreement is, solely in the interests of editorial clarity and transparency?
Otherwise, I suggest that you establish a policy to throttle back on such submissions.
The point is simple: most credible publications avoid allowing a zealot to publish something, then republish to rebut comments, then republish, ad nauseam. I don’t think you understand that the nausea level has been exceeded.
Often privately, Mr. Flood and I have disagreed on some matters and agreed on others, but the volume of his effluent is really offensive, and your tolerance for printing anything he writes is appalling. Put him back on the payroll or use the same letter to the editor constraints and limitations that other responsible periodicals around the country use.