He said he has received a lot of hate mail for killing Janeway and has told these angry fans that the decision was not his and that he wrote the possibility of her return. Apparently some individuals have written him some pretty venomous comments.
That doesn't surprise me. R.A. Salvatore got a lot of hate mail (and, supposedly, death threats) because he killed Chewbacca in Vector Prime
, his first Star Wars novel. There are some people out there (just a small minority, thankfully) who, unfortunately, take their love for fictional characters to absurd levels.