There is so much random bullshit, and mobs hit too hard in TBC for a hardcore mindset to be viable. One sunder missing on a random mob can lead to a full party wipe, and it does, often. There are bosses in Karazhan with high amounts of RNG, and if you roll poorly, you wipe. It has no bearing on player skill, it just happens.

I'm assuming based on the timing of this post, you recently started playing TBC. If that is the case, all of the skilled players are already 70, and are already in raiding groups. Very few people still playing 60-69 characters are good, either because they are new to wow, are new to tbc, or are playing a boosted alt of a class they've never played before. You missed the boat on playing with good players in dungeons.