It's pretty easy to understand...
Giving a respectful opinion about a piece of music (positive or negative) or about a musician's performance, is fine.
There really are no double-standards. I'm not a fan of much of DT's modern era output. I exist just fine here, without issue. People need to stop taking others' opinions so personal.
not to pick on Blob (and I'm not, Blob, it's just this example comes to mind), but if someone loves Awake, and posts a thread about it, does it really require someone coming in and taking shots at that particular opinion? Of course not. For the sake of discussion, if a person has to comment, you can simply say: "My opinion on it is well documented, so I'll be brief. I just don't think the record has *insert descriptive term that sums up your feeling* in comparison to some of the other albums. But hey man, glad you are diggin' it. Some good songs on there."
Bang, done.
And then after that, people need to stop sniping at others' opinions. It's called constructive debate. The problem is (not talking about ANYONE specifically, because I honestly just remember posts, not people for the most part) that folks just nitpick for the sake of nitpick, which gets on the nerves of some folks.
Just detach yourselves and have constructive conversation. Hell, bosk and I disagree about a ton regarding Dream Theater. And we never have any issues (other than his bowing down before the altar of Y&T's "Summertime Girls" which to this day, I don't understand).
In a nutshell, people take stuff too personal and then push buttons. Detach and resist the urge. It'll result in a better forum.