Read the whole thing.
There is actually quite a lot of ethically questionable behaviour in the classical music world, some of which might occasionally raise to the level of genuine corruption. One thinks of things like competitions rigged in favor of the students of a particular teacher, or conductor competitions with suspiciously hefty entry fees, or glowing reviews of CDs purchased with real cash. Instead of talking very much about these things however, we seem to find more articles about a few orchestras that do not seem to have the statistically correct number of female players. Mind you, over at Norman Lebrecht's website, no opportunity is missed to stir up dirt whether deserved or not.
Of course, the proper thing for any music critic to do would be to purchase tickets to any concert you are going to review, just to avoid the appearance of favor. If this is too expensive, then the publication/employer needs to pay. As Deborah Jones mentions, though, this would be in an ideal world, which we don't seem to live in. What professional record reviewer actually purchases the recordings he reviews? No-one, I suspect.
I wonder if this situation might not be alleviated if the actual criticism itself were clearly related to stated aesthetic principles and not just some personal reactions tossed off right after the performance. If a criticism is based on something that can be shared objectively, then the potential of perceived bias surely would be reduced. But maybe that is more wishful thinking!
Let's end with an opera mentioned in the blog post. Here is the "Queen of the Night" aria from the Magic Flute by Mozart, sung by Natalie Dessay: