Alan Moore - Hypocrite

Now I've not read the graphic novel, nor have I seen the movie the whole way through and I am aware that there are some major differences, but my point concerns a few of the characters.
Alan Moore is notorious for getting annoyed at films which he thinks 'ruin' his work, but doesn't he ruin other people's?
For example, I am not aware of any version of the Dracula story where Mina Harker becomes a vampire. Yet Alan Moore decided to make her one.

Dr Jekyl and Mr Hyde. I haven't seen how he's depicted in the graphic novel, so I may be wrong about this, but in the film when Jekyl turns into Hyde he grows to Hulk like proportions. If the graphic novel is similair, this has been changed too. As far as I'm aware Dr Jekyl and Mr Hyde look the exact same, only Hyde is evil,perhaps there are more differneces but nothing as radical as what I seen.

Dorian Gray. I'm admidatley a little rusty on this, but I know Dorian Gray keeps his appearance and his portrait changes, but does he have the power to re-generate?

Lastly, Tom Sawyer. Ok I know Jack about Tom Sawyer, but from what Futurama told me, he paints fences.

I accept that if these characters were true to the source, it wouldn't make much of an adventure story (perhaps a good buddy movie though!) But my problem is with Moore for moaning about people changing his work when its made into a film, It's clearly done to make it more interesting. Yet somehow it's fine for him to change the work of Stoker, Twain, Wilde and Stevenson for the purpose of his graphic novel?

Anyway, that's my two cents! Thanks for reading!