This post won't be about the arguments for and against, there are much better people than I to present those. I'm more interested in why the authorship debate inspires such ire with those of the opinion that Shakespeare is the genuine article. After all, surely the play's the thing, not who wrote it. What does it matter who wrote the work as long as it can be performed and celebrated?
I can't speak for others, but for me there's one big reason.
There's a sort of snobbery in asserting that a man from Shakespeare's background couldn't have written the wonderful things he did. And Romeo and Juliet. Shakespeare wasn't a peasant by any means, but he wasn't a nobleman or of the higher classes. There's an undercurrent of classism with the anti-Shakespeare argument that grates on me. Why couldn't a man of modest means have an incredible mind? Oh no, it must have been an aristocrat. Only one of higher breeding could know courtly details (That could have been read about, or, you know, made up) or have the intelligence and imagination to create these wonderful worlds.
Heaven forbid he should reach beyond his means. That the upper class descendants and supporters of the Oxfordian or Bacon camps want to snatch the credit from a pretty much ordinary kid-made-good smacks of elitism, and that really bubbles my cauldron.
If there was a genuine case to answer then perhaps I'd be more open to the arguments, but as far as I can see, the only real reason to dispute the authorship is Upper Class sour grapes.