Lol, thats just a bit misleading. You can't accurately replicate the look on a screen with a different dpi anyway, especially not by upscaling a image file. You end up with multiple pixels representing 1 pixel or blending in between which is why it looks so weird.
The 3ds is 1on1 on all sizes, images aren't stretched, its pixels size is just. But I guess to some it does FEEL this awfull
Also since the original model the gpu supposedly supports native 2xAA, at the cost of render power. The usage of which is up to the developer. With some games if you turn off the 3D AA kicks in, it doesn't make a huge difference but is noticable. Personally I find that having the 3D on full still looks better, maybe because my brain interpolates the 2 different images
But still, pick whatever FEELS right for you!