As kiamlaluno describes, there is a new feature that removes these salutations when the post is entered. But your post is over a year old and this feature is only weeks old!
The key part is at the very end of the answer that kiamlaluno posted (Jeff Atwood speaking):
I've also removed most of the salutations (per above) across the network from existing posts.
Interestingly, it seems like the removal was done on a database or dev-access level. If my voice counted for anything, I would have said that it should be done as a revision by Community, with a comment like "Removing salutation according to new automatic filtering rules", but maybe the number of revisions generated would have been too expensive.