I am strictly a Fiverr buyer (I did try selling a service a while back but after two unsuccessful sales could see it would be more hassle than its worth for what I was offering!). Suddenly I now have a Response Rate bar showing 67%. The truth is I might not need to respond to a seller - especially if it is relating to a request where I have not chosen that seller. The sellers will also be replying to me from now on so their Response Rate bar is kept higher. Its a no win situation this and cant see why buyers also need to have a Response Rate bar.
I think its showing because you used to sell gigs. Its the only thing I can think of at this point for Response Rate to be showing.