So, this is kinda weird, but general colors didn’t have names for a long time. Like in Greek texts by Homer he describes the water color as dark wine color because the name “blue” wasn’t a word. So it’s possible when they named a “red onion” purple wasn’t a color and considered a shade of red.
Also as others have said purple was the color of royalty and they didn’t want an association.
So you fear and hate someone who didn’t understand your opinion or point of view? I can’t say that’s ever honestly been a thing for me. Everyone doesn’t need to understand or agree with you, and that doesn’t make you wrong or right. If you’re that angry at someone on an anonymous online forum maybe you should seek some sort of help, legitimately I’m not trying to be mean or condescending.