Wait, are you saying you are comparing real world 3.x conversations to internet 4e conversations? Because if so, that would be your problem. Real world conversations come down to "what do we want at our table", in an internet conversation, that's pointless, people want to find out what the rules do/are supposed to mean, and then they go home and decide if they want to change it.
I agree. I think internet discussions have changed the dynamic a lot. Yes, the attitude was there before the internet was widespread, but I believe it is more noticeable and pervasive because of internet discussions.
When you discuss rules online there are a few approaches to what you can discuss.
1) Rules as written - As discussed here, you can discussion what the words actually say. Sometimes the words are ambiguous, but often they are very clear. That leads into discussions about whether what is written makes sense, which gets combined with approach #2.
2) Rules as intended - Much more important in my view, this tends to get short shrift on some internet discussions. The main issue is that it's often hard to get into designer's heads as to their meaning, and only a handful tend to discuss such rules online. Even when they do some even disbelieve their comments as covering their butts, which isn't helpful in my opinion.
3) Rules at the table - Using the information from approach #1 and #2 we then can discuss what is the best way to play at the table. This is complex for a lot of reasons.
Each group has different dynamics and what works best at one table won't necessarily work at others. Also, it's nice to have a consistent ruling when you play at different tables. If I have 3 different games I visit in a month, it can get confusing when a rule works differently at each of the 3 games (especially when you add all the various rules that work differently and try to keep track of them).
Also, on some forums this discussion also involves house rules which have a separate forum. When a discussion touches on this issue some feel it belongs in the other forum and try to quash the discussion, In my opinion, it's not reasonable to expect to hold a cohesive discussion on one issue in two separate threads. Still, I understand without the differentiation the rules forums might be 90% discussion about house rules.
Give the side issues with approaches #2 and #3, I think many try to limit their discussions to the RAW. It's a much easier place to get a solid basis work with. Even when it's ambiguous, it's usually much more straightforward that the other approaches.
Given this tendency, I think a lot of people have gotten into the habit of discussing RAW and bringing it to the table, forgetting the other approaches. They then start considering the RAW the only basis for a baseline and consistency.
Personally, when I start running a new game or edition of the game I try to run it by the RAW, RPGs are complex, and often changing a rule has repercussions on other rules and campaign balance that aren't immediately obvious. I only go with a different approach when the rule obviously isn't working with the group. Once we get a feel for how things fit together, that's when we start adding house rules. We are judicious because too many house rules are hard to track, especially when new expansions to the game might interact with the house rule and have to be approached and dealt with.