I've been a long-time lurker here (although a new poster), and I think what you're noticing are the postings on just a couple of boards where people are very unhappy with the liturgical turn the Church has taken over the past 40+ years. At least, that's where I see the most disgruntled posters.
This is a VERY conservative online community, for the most part, and many people seem to be much more concerned with the letter of every (even obscure) law more than they are with charity toward others. Their world is extremely black and white and focused on rules, sin and judgment -- not love and mercy.
It makes me a little crazy to think that this is the face of Catholicism that others online see, when true "church" happens at the parish level.
The medium of online communication usually sounds harsher than the poster means, also -- there's just no way to convey "voice" here -- which could temper the tone of the posts.
If you read the posts that ask for personal advice or prayers for a serious situation, I think you'll find some of the affirmation and kindness you expect.
It also seems to me that the unhappy, complaining people are those who tend to post more frequently and without obvious charity -- charity toward them may help break the cycle.
(You'd better read this fast - it may disappear any minute ;-) )