Apple IIc text is red and hard to read

As you probably noticed, the text is much clearer when the "monochrome" button of the monitor is pushed in. That forces the entire screen to display without color by disabling the monitor's (NTSC) color decoder. With the button out, the monitor is trying to decode color information from everything the Apple sends through its composite video output. The text in the bottom 4 lines does not have any color information, but the monitor doesn't know that. To the color decoder, the sharp boundary between the black background, the white vertical lines of the text, and the black background looks like it should have a strong color.

The monitor's color decoder is also disabled when the monitor can't detect a "color burst" in the retrace interval. This is called a "color killer" circuit and is originally designed to prevent random color noise from appearing on black and white TV broadcasts. When the Apple II is in TEXT mode, a circuit in the Apple disables the color burst, which in turn makes the monitor switch its color decoder off. So you won't see the color fringing in TEXT mode.

This problem is somewhat more pronounced on the Apple II compared to systems that have real NTSC color encoders. The Apple uses a kind of shortcut called "artifact color" that saves the complexity of implementing a real encoder, but the result is that there is a color fringe effect.

This is Double High-Resolution - a graphics mode in which the color-killer circuit is off, since it is not a text mode. In this mode 80-column text will always look like this over composite NTSC on a color monitor due to artifacting.