As a Pagan, and an author of spiritual based hubs/articles here and on other places, I get a regular flow, at times, of hate mail from those who think Paganism in a any form or fashion is evil and such. This all comes based on misconceptions that are out there.
How I deal with it is one or two ways... If a person is rational, and not too mean, lol, I will take the time to clarify the issue. This has been a good method when doable, and i have gained some great friends.
If the person is just hatefully hateful, then I will spam em and be done with it....and/or block them wherever they may be messaging me from.