This issue seems to be getting a bit out of hand. See Should I remove 'fluff' when editing questions?
A couple of quotes from that page:
Yes, absolutely remove such things.
Anything that is not relevant to the question/post is noise and should be removed.
That includes salutations, signatures, 'thanks' and the kind of content you have highlighted.
Should these sort of edits be made if this is the only change?
I would not recommend making these changes as the only changes in a suggested edit (as the OP's rep would require.) If you have full editing privileges, that's different.
After talking to other moderators just now the thinking seems to be that removing "Thanks!" and nothing else is a rather trivial change. It would be different if you found spelling and grammar mistakes and fixed those as well.
By making tiny edits you are forcing other people to go through these edits and approve them, which is wasting their time if the edit is trivial, and if they still have to make more substantial edits of their own to get the question into proper order.
While I was typing this Shog9 responded. He is one of the Community Managers at Stack Exchange (a level up from a moderator). I would listen to his advice. :)