Shimano did another silly gimmick in around 2001, with rapid rise. The mech's spring takes it to bottom gear and you pull the cable to take it to smaller sprockets. This causes all kinds of wonderful things to happen...according to the marketing department.
In reality, what it means is that downshifts require the force of the mech spring to push the chain onto the bigger sprocket, instead of your thumb force down the cable. That means very light shifting, but when the spring slackens with age it becomes erratic, especially under load. I never found my thumb was so weak that I couldn't shift down, so it was a solution to a non-existent problem. Typical Shimano marketing.
Most people hated it, which is why Shimano went back to the conventional 'high normal' system.
You will find the cable clamp is on the inner parallelogram arm instead of the outer.
It's a cruddy setup, so swap to a conventional mech and live happily ever after.
The one thing in its favor is that you have identical up/ down buttons for shifting on the bars, and for bar-end levers on drop bars it keeps the lever out of the way of your knees when you are most likely to be out of the saddle.
Ride it or milk it!