I strongly encourage anyone reading this to abstain from adding unnecessary salutations to their questions and answers. This isn't a discussion board, answers are not replies, and if the majority of each question's excerpt quoted on the front page of the site is the same then you've thrown away what should have been an eye-catching introduction to your question...
That said, if you're gonna edit these things out, be polite about it - and don't stop editing after removing the salutation:
To be very specific, I would discourage editing a post solely to remove salutations like “hi” and “thanks”. That’s just adding an unnecessary edit on top of an unnecessary set of salutations. I completely agree that salutations add little to a question or answer, but if you’re going to take the time to go in and remove salutations, fix the whole post while you’re at it! If there’s nothing else to edit, then don’t bother.
The reason for editing someone else's post should always be to improve it, to turn the question or answer being edited into a shining example of the best your community has to offer. Don't get hung up on trivial little edits.