On the Balance of the Negative

Soo, how do we as a community say something negative?

I'm sort of awestruck by the consistency of the output and the unabashed positivity of the 'community' of bloggers. Some of that seems like a natural outgrowth of a decentralized posting area - obviously in a forum people of wildly differing opinions will congregate and post, whereas in a blog, you will only typically acquire followers who approve of your message. In the short run, this creates like a positive, can-do type of environment, subject to high duplication of creative output and a poor indexing method. Some of which is being addressed.

However, the longer I am part of the community, the more issues that are contentious and possibly may reflect certain people or products in a negative light rear their head. What is an appropriately positive way to discuss these issues?

I've already encountered a major issue in this regard, due to my A-Z posts. I had never really read any of the Forge theory before I started and discovered numerous issues with both the methodology and some of the core points.

But where do I stand critiquing the thousand+ hours that man has spent thinking about and codifying his theory? How do I provide criticism or critique that is both effective and constructive, (a difficult challenge for me, being my default conversational stance is "inflammatory")? How do you say something on a blog that's critical and yet does not dampen the enthusiasm of the poster?

More importantly, how do we, as a community, have a discussion about something complicated, like charging for .pdf's versus free .pdfs, or duplication of work and intellectual property rights vs. not being a dick without being negative?