Is it more likely that unity has put their company at risk by doing something which hurts their community? Or is it more likely that a few members of this million person community are unhappy about some new community guideline?
The forum changes are really just the straw that broke the camel's back for many of us. What Unity says and what they do are two different things. Just a few weeks prior to the forum change, they changed payment processors for the asset store so many people from the US can't make payments. I about had a heart attack when my debit card came back declined. They've changed pricing strategies twice during the 5.x cycle in ways that angered Pro customers. They dump news or drastic changes on us and then don't stick around to respond to concerns or complaints. They have almost zero engagement with the community they claim to love and respect so much. So it isn't just forums I'm looking to replace. There's a good chance that my next game will be made in Lumberyard (if they get proper FBX import working) or Unreal.
When you rely on a company's product to earn a living, you want to know that the company has a similar vision to you. Instead, they've made it harder to get payments for assets, which effects the income of asset store developers, they've made it significantly harder to communicate on the forum, which makes it harder to provide support for those assets. And we have no idea when the next change is going to come down the pike and how it will effect our ability to do our jobs effectively. All of this might be fine if they would engage more with the community. But alas, they don't.
It isn't just a guideline change either. The software they've switched to doesn't even appear to be made for forum usage. If you edit a post, you are given fields for regression status and FogBugz ID numbers. Huh? Doing anything at all, including posting a reply to a thread, requires a new page load. Hit boxes for what should be simple URLs don't work right on mobile. The new moderator controls are so complicated that moderators are refusing to even use them. Notifications barely work. There's no Ajax or dynamic content to be found out the site aside from a popup when someone likes your post. It's bad.
If things don't change, I think we'll all be glad to have a forum to come to and actual discuss game development or related topics without all the constant negativity that Unity brings to the community. There are too many things in this world to annoy me without my job being one of them.