Things that are completely free and worth your while that also have a substantial cost to the provider (in terms of both time and money) rarely stay completely free and maintain their quality of service unless the person providing them has unlimited resources to dump into providing them. Personally I see the (really inexpensive and completely worth it) admission cost to one section of a much larger site as a way to keep providing the free service you enjoy long-term. You'll remember some of us donated money to send Zod (yeah...I can't bring myself to just call a guy I don't know by his first name like we hung out last night) to Miami as well...there's precedent for people around here being willing to help out.
I haven't seen any indication myself that the free portion of the site (much much smaller than the paid portion of the site, for the record) is being abandoned...that seems like a completely unfounded way to justify complaining about the additional content being offered to those of us who are willing to help support something that "we have had for free for a decade or more"
This is one of the most well-run / easy to tolerate NFL team boards I've had the pleasure of reading...and if $5/mo helps keep it that way I can have one less shot at a bar. Or one less whatever else. Or I can just have all the things I had before and have 5 fewer dollars. I feel like the value I get out of this place, even without the extra forum, is more than $5.