I've seen this a lot. Why do people constantly say thanks? Is it an automated response to rating? Or are people just thanking others for making puzzles? I know no one requested this, I don't even take requests. I'm confused...
It is not automated, but appreciation of those that create good quality logical puzzles by those that solve them. They may not have anything further to say by way of review but that does not stop them being appreciative. When choosing to solve a recent puzzle I look for comments like thanks or 100% logical as ratings can be unreliable until a reasonable number of contributors have rated a puzzle. So thanks for the time and effort that you put into a puzzle that I enjoyed solving.
I say thanks because I appreciate the effort made by the person to create a puzzle that is logical and fun to solve. If I see the word thanks in the comments section it lets me know that I'm not wasting my time trying to solve a puzzle that isn't logical. I think we should be kind and show our appreciation for all puzzles.