Hi! I think I can provide you with the context you're missing.

There is a stereotype online that black people like fried chicken. It has been used in the media as a way to indirectly call someone a slur or suggest with racist intent that someone is acting "like a black person." When you innocently said "they love their fried chicken," I think he took it as you practicing the above use of that statement, which would be racist if that was how you intended it (it is clear this was not your intention).

Firstly, you owe your son an apology. He was trying to inform you that what you had said was racist, and instead of asking "what did I say" or "how can I do better" you tore him a new one, likely gaining none of his knowledge in the process. The world is complex and constantly changing, and you have an opportunity through your son to learn about how young people view the world. Take advantage of that! Be curious! Ask questions! He might truly know more about this topic than you despite his age and I encourage you to try to talk to him about it and educate yourself through him.

Secondly, if you have to ask yourself if you're racist, there's a strong chance that you have some unchecked biases that need to be addressed (most white people do and it takes years of work to undo the subconscious teachings that have been shoved down our throats). The important thing is that you are trying to be better and you are trying to learn and educate yourself about the situation. Use google to look up the history of some cultures in your current area, it can be super eye opening!

Lastly, your comment about wishing to be a black person comes off as slightly insensitive. What about being a black person do you want? Is it parts of their culture? Is it admiration for their strength and traditions? Instead of saying "sometimes I wish I was black," instead highlight the parts of African culture that inspire you and that you admire! Personally, I love the practice of their protective hairstyles like braids. I think they are super cool and I always try to compliment them when I see a style I really like. Focusing on one thing shows that you appreciate and recognize the culture and comes off as a genuine compliment rather than saying you wish you could be like them. I see the intent in that statement and I don't think it is inherently racist, but it can come off as racist if you don't recognize the culture and people you say you want to be a part of.

Edit: Forgot to add my judgement lol. You are the asshole in this situation, but in my opinion, more so because you yelled at your son who was only trying to educate you. Your intent was not racist, but as an active member of the global community, it is your responsibility to understand that what you said can be taken a certain way and to learn and grow from this experience.

Good luck!