Danny lived in Britain, where being a redhead can be... Well, a life of bullying as a teen and child, even as an adult.
Once he moved to America, he knew he'd get mean comments on his hair, it's happened but rarely and usually from Brits.
He met Adam there, a clone. Danny didn't know it, however.
In real life, The Catholic Church hated The Vikings and they were told by The Vatican to see redheads as being of Viking blood and therefore evil so they were encouraged to eradicate them from the Irish population, Unfortunately.
They were wrong because Celtic genes also gives people red hair as well so they were literally punishing themselves - for being themselves...
It was very wrong for them to do, even if they were of Viking blood, it wasn't right to harm children and innocent people based on their hair color like that.
In real life, in the past, while this doesn't mean that you do witchcraft, red hair was often seen as a marker of witchcraft and heresy and it was persecuted by the Catholic church. In fact, it's said that the Spanish Inquisition targeted redheads, viewing all those with red hair as Jewish heretics. In this light it's logical that red hair would become a badge of honor amongst those who opposed this unholy Catholic empire.
Please note this: Most Jewish people don't have red or orange hair at all. Most have black hair. and even brown.
Danny had the brunt of bullying, even encountered a rare thing, getting beat up at random for his red/orange hair.
Danny was happy to be in America, his mom loved him and his dad too but his grandma from his mom's side of the family would always yell about how she hates redheads, his mom would meet redheads and dislike them immediately at first due to this and the fact her ex idealized them.
The only redhead she quickly liked was her son, she was definitely disappointed in his red hair which she titled "Dead hair." His dad stopped her from making this comment and told her she'd respect him, his father had red hair.
His mom only loved his father because she got to know him.
His father was subject to bullying more than his son and thus raised his son to be a good man like he was ad be proud of his mob of red hair.
Danny is ranting to his mom.
Danny says "You know why some redheads seem mad and hotheaded? People are mean to them, that's why. If you insult someone on purpose, even for a joke, they'll get mad, how are they supposed to know you aren't a jerk who means harm to them? We get fiery because some of you all make us angry on purpose. Getting insulted in high school and other people staring at me, I know it could be for other reasons but after being attacked for your hair so much over nothing, it seems like they hate you."
In real life, Men and women have pretty differing experiences though, this is a key thing to remember as well.
Redheaded dudes tend to get teased for it more openly, but its usually just playful banter.
Redheaded girls tend to get Pidgeon-holed a lot more by it and be on the end of more social bullying.
They can get a lot more sexual attention for it also, but then again *they can get a lot more sexual attention for it,* often in the form of harassment or even, sadly, sexual abuse.
Male redheads tend to struggle on the other hand with a lot of feelings of inadequacy and undesirability, especially if they're overweight for most of their lives.
At the end of the day its not a huge deal, but it is a big part of your identity, and shapes the person you become in a number of subtle but deceptively profound ways.
For ONE REAL REDHEAD, he found that the (England) English reaction to it has always been the closest to actual active *hatred* he's ever encountered, even as an adult. It's gotten a lot easier after he moved to Scotland (Where it's obviously fairly common).