AITAH For accidentally being racist because I didn't know black people were associated with monkeys?

I (19M) Was on discord last month and I figured I'd post something out of context in a discord server to try to be funny because I love out of context things. What did I decide to post? Well I posted a monkey performing a backflip. What I didn't realize was people were talking about black people prior to me posting that and this Made someone angry. This person we will call Clark (Now 37M I think?) Clark responded with "I guess you aren't OK with racism unless it's against black people. I don't think I feel like interacting with you anymore." I was confused because I thought we were joking around. (I have autism and can't understand certain social ques.) Clark blocked me shortly after. Then the server owner messaged me bringing this to my attention and this was when I realized that what I posted was racist. I messaged various people about this and they all pretty much gave me the same advice. And I'm doing my best but I just can't truly let go of this even after a month. I'm curious of your guys perspectives on this because I think it'll make it easier for me to let this go. Here's where I ask, AITAH? Edit: It looks like according to most of you guys who read this, it looks like I'm NTA in this situation. (You're still free to have your own opinion.) Update here: https://www.reddit.com/r/AITAH/s/GgVr1YJAFX