Oh come on now. You have memory, and then you have virtual memory. If something is not being actively used, but is using memory, Windows will push that program out to the swapfile and use it for something else that is being used.
For over 20 years now, Windows has managed memory for us. It is NEVER a "OMG, Program XX used up all my memory and wont release it" situation. Our computers are smarter than that.
Memory is there to be used. Use it. Don't complain because some awesome piece of software uses some of it. That is what your memory is there for.
Perhaps, you would rather remove your hard drive, put a see-through panel on the side of your computer, and add some lighting to the inside of your case so you could sit there and stare at those amazing memory sticks you have mounted in your motherboard. Because without a hard drive, those memory sticks would be 100% available for something you can no longer run, because you have no hard drive to even load anything into your memory.
But it would look "purdy!"