Good review. I agree with your points.it's not the complaint about no follow tags but it's question about attitude. who cares for no follow tag here. If i have a quality site I will have natural links any way without spending a dime.
It's about some people thinks about members who add links in signatures are spammers, and that's not a healthy discussion any way.
This forum has started 2 SEO contests, why adding a link to forum made essential? People may question why links to 2nd contest has been changed all of sudden?
A member to the forum is a contributor. People do spend lot of time reading and commenting to posts. This that means every one is looking to gain something out and they have to reciprocate to forum?
An understanding of visitor's psychology is more important running a forum. People need friendly atmosphere and they don't come here to be humiliated.
This is my personal view points, you may think other way