To put it shortly, Aperture is, besides being a database, a photographer's tool, a dark chamber if you will, whereas Photoshop is a manipulator's tool, a cheater's tool. PS and Aperture (or Adobe's Lightroom) are entirely different beasts – you're comparing a screwdriver to a socket wrench box. If you need sockets, that's fine, but if you need to put up a picture on the wall, you propably want the screwdriver.
This is probably the simple response:
Photography is manipulation, everything about it is about manipulation.
I think you misunderstand how I use Photoshop. I'm not adding zombies to landscapes, though that's a valid use for something used to make art—maybe not a traditional photograph, but for art.
Both programs are photographer's tools depending upon how you use them. I have plenty of experience in physical darkrooms—I even plan on building my own when I frame out the inside of my garage/shed so I'm pretty familiar with what is possible.
I like Photoshop because it's easier to make selections to apply adjustments to—like a simple levels or curves if I'm working in color. It also lets you work on images as if you had a certain filter on the camera. I know all of this is probably possible in Aperture, but I haven't taken the time to learn how to do it because it doesn't seem to allow masking like I like. I also think Photoshop's handling of Camera RAW files is akin to most of what is possible in Lightroom. I've used both, but I've used Photoshop way longer so I go with what I'm familiar with. I also don't like Aperture's workflow. I know it keeps the original intact, but it always feels unsafe to me because I'm not controlling it directly.
Thinking of Photoshop simply as a tool for manipulation—and thus a cheater's tool as you put it for some reason—comes from a holier than thou attitude. They're both tools. You could make crap with both! It all depends upon who is at the helm. Look at Uelsmann's photos. His manipulations would be simple to do in Photoshop, and yet he did it by sandwiching negatives and using multiple enlargers and masks. No one gets it completely right in camera either, not even Ansel Adams—he heavily processed his film to get the latitude from it that he wanted.
I've made
this in Photoshop and I've made
this in Photoshop. The first one is probably not possible in Aperture. The second one is. If not, it's possible with some grade 3-5 paper, a #5 filter, and some extra time with an unfocused version of the image printed over top. Instead I did it with Photoshop using a handy recipe of a B&W adjustment layer, a Levels adjustment layer, an Exposure adjustment layer, and an Unsharp Mask.
Sometimes I like to play with my color images. Sometimes I don't. What difference does it make that I've cross-processed it in Photoshop or with chemicals and film? It's the final image that matters. We're making art here. It's not a technical exercise. Who cares if I lay a texture over my image to give it a different color? It's how I want it to look and it could be done in a darkroom if I really wanted to, but not in Aperture. So how can one make the argument that Aperture is a photographer's tool and Photoshop is not?