How to criticize people

I am a big Harry Potter fan.  I have read all of the books several times, including the minor books like Fantastic Beasts.  I cried at times when I read "The Cursed Child."  I purchased and viewed all of the HP movies many times.  I use Pottermore and other websites.  I went to the theater on the day that the movie "Fantastic Beasts and Where to Find Them" opened in my area.  I bought a ticket for the very first screening.  Well, I hated the movie for a whole bunch of reasons.  The first thing I did was to send a tweet to J.K.Rowling herself. She will probably never it read it but maybe one of her assistants will give her a tally of the positive and negative comments.  The next thing I did was to go to the Harry Potter websites.  I argued that the movie was historically inaccurate.  I mentioned that shooting a movie in sepia colors doesn't make it historic.  I had about ten other reasons why I thought this movie was awful.  The response was dramatic.  How dare I criticize J.K.Rowling?  Didn't I realize how eagerly her fans had waited for the movie to come out?  Didn't I realize that JKR wrote the book and the movie script?  Well, that was what I was trying to say.  The movie was what you would expect as an amateurish first attempt. Perhaps JKR will write a better script next time.  I can tell you that I am extremely unpopular among JKR fans.  So I went silent for two weeks.  The initial reviews of the movie were glowing.  They always seemed to mention that the movie was making a lot of money.  By the second week, the reviews were less enthusiastic.  The last time I checked, a few vloggers and bloggers have been critical of "Fantastic Beasts."  I think that most fans will finally decide that this movie is a stinker.  Everything I have been saying is leading up to one key point.  Sometimes timing is important when you want to say something unpopular.  I think that tweeting JKR directly was the right thing to do before criticizing her movie.  If I had to do it over again I wouldn't have been so quick to criticize something that people had waited for.  Next time I will wait until  the time is right before verbalizing my opinions.  Maybe I will try to be less harsh at first.  Sooner or later most Potter fans will reach a common conclusion about this movie.