A:
No, it's not appropriate unless the organization has a special rule of order limiting debate in this manner.
Every member has a right to speak in debate, regardless of who was lucky enough to have spoken before him, except when restricted by a two-thirds vote (i.e., Previous Question or Limit or Extend the Limits of Debate.)
(RONR p. 380, 382.)
As for "harangueing," RONR pp. 382-384 does limit each speech a member may make to ten minutes, and to no more than two speeches per person.
Many societies have their own special rule which supercedes this, limiting debate to, for example, three minutes.
I agree that many times "debate" tends to be a lot of "me-too-ing."
I believe a skillful presiding officer can artfully and tactfully suggest that the group could move on to other matters, without violating any member's right to debate.
That right is paramount, but the desirability of moving along can be persuasive.