The point is, how far does it go that moderator knee jerk reaction is never to draw a line at what is "deemed" spam, and then banning someone. A ban is the last thing to be done and should only be for abuse, attacking others and that type of thing, warning (Via PM explaining why they were warned and what would happen if they do it again), banning from a thread should come first.
If that person has had warnings then banned from thread and then carries on then yes, but (I dont know full details) if mod is hitting ban buttons just becuase he presumes spam ... thats poor and they should be taken away and job given to someone else. Remember a ban is a ban from the entire forums, if it was spam in a thread based on requests (hardly abusive and offending anyone) then ban them from the thread only.
Also if the forum is run right it should have sticky and warnings about this about what steps a moderator will take, some people may not know and quite innocently request something again as they were not sure how the response should work and then they get banned from the forum ... to me that's poor running of a forum.
Stupid thing about it is, the nature of modding way or anything like this is about content and the public and requests so they should expect some of this and work around it than insta-ban. Its like working at a counter in a shop and banning people for asking for certain items they dont have, you put a sign up about it on the door to save people asking etc.