I actually think these are pretty funny, not very offensive. The caption for the first one is just hilarious, IMO.
TBH, though, I think perhaps you have relied too heavily on gradients, and isometric design. Also, it seems that while the images have a relatively good grasp on lighting, not much is taken into account for shadows. The apple is one of the only things in the image that can't be drawn in the isometric formula the way everything else is, and I think that is what is most lacking here. You should do yourself a favor and abandon the dithering. It can work, but until it works without the dithering, it likely will appear to be a cover up.
Don't be afraid to freehand the lights on the apple. you want subtle vertical streaks and glossy highlights, with speckles throughout. Definitely want to up the contrast there, could probably do it with fewer shades and a single, maybe 2 highlight shades.
You are on the right track here without a doubt, I like the style and the sense of humor is fantastic. Try to start designating a larger three dimensional space where you can account for a single (and in the future multiple) light source(s), and then draw highlights and shadows based on that. Don't be afraid to look at references for things like apples, too. You don't have to be photorealistic, but it's healthy to train your eye on what things really look like, and how light really interacts.