I've touched on this subject before but, like a boomerang, I return.
There are some people out there who, lacking something better to do, question why writers produce Sherlock Holmes pastiche or homage works. The accusation that is often levelled is that these authors lack talent and have to use the Holmes name to get their books noticed.
I hate to break it to these people but writing a half-decent Holmes story requires a hell of a lot of skill. It's like walking a tightrope - you don't have to stray too far before you plummet. Anyone who even attempts it and, furthermore, makes it publicly available, is showing a considerable amount of bravery regardless of the quality of what they produce.
I also wonder why this "rule" is not applied more evenly. Did the writers at Marvel invent the characters of Thor, Loki, Odin etc.? No, they didn't. They took already existing characters and put them into new stories. Do we hear them being called talentless for doing so?
Neil Gaiman didn't invent the characters of Death or Lucifer yet he does not get grief for utilising them in original stories. The fact is that characters are reused again and again (copyright permitting) and often because the audience will have heard of them and be tempted to find out more. So, there is no justification for solely giving Holmesian pastiche authors this grief.
I also think some people judge pastiche works harder than those of the original author. Let's face facts, Sir Arthur wrote a few stinkers (e.g. The Mazarin Stone and The Creeping Man) yet he does not get criticised for them all that much. But if a pastiche author wrote a story like that they'd be metaphorically nailed to the wall.
If you are of the opinion that the stories of Sherlock Holmes ended with "Shoscombe Old Place," no one is compelling you to read anything else. Getting angry about it makes no more sense than getting angry about modern Holmes, gay Holmes, or supernatural Holmes. The great thing is that there is choice and you can elect to read (or not) what you wish. You have the freedom to choose the bricks with which you build your Holmesian world.