No, it's not. Which is why, if you really really must reply to messages
like that (and I'm not sure I see why you must), you should at least not
quote the entire message, thus duplicating the offense (such as it is).
In fact, in this particular case, the original message had already been
blocked by my ISP as spam. Had you not copied the original post, I would
have been happily unaware of the original spam altogether.
What that has to do with anything, I'm not sure. The spam was selling
Islam, not Christianity. And regardless of which religion was being sold,
as everyone should be aware, among all religions there are always some
followers who don't seem to know how to behave, at least according to the
usual rules of society. What's the point of an editorial comment on spam?