It always amazes me how the views on BM shift so much.
Back in the day, it used to be considered a noob spec because everyone considered it weak (always). That's when I first specced into it, and I still played it effectively. Then the 1.7 changes came, and people considered it a noob spec because they thought it was overpowered. Still, a large number of people continued saying it was a weak spec.
Now that it has been proven to be a viable spec, more noobs are playing as BM (whereas it used to be a very rare spec), so we have even more divisive views, violently condemning BM as noob spec for being easy... then just as violently condemning it as an unfit spec.
In the end, when the comments always return to raiding, it furthers the idea that it is the player, not the spec, that makes a difference. It's more than just picking talents, it's also about speccing the pet and using its abilities effectively.
BM is more involved where raiding is concerned. It takes some focus to effectively use both the pet and your own attacks to their fullest. That's why many Beast Masters break down when it comes time to raid. They can't handle the duality.