Yes it is. It's just a silly and arbitrary thing to redefine a color as having only 1 frequency. If you know about music and sound you'll know about something called timbre, it's what constitutes a characteristic sound.For example a C note played on a piano sounds different from the exact same note played on a violin, same note different timbre.
Colors are like timbre. It's not in vain that timbre is also called tone color.
Also magenta is just one in many colors that are like this.