Is there some joke or clever thing I’m missing?
I think the meta-joke is “ASD people do things that neurotypicals think are weird, but make sense to them.” Like calling a red shirt blue.
I smiled.
Oh, and I probably should mention - it refs the Light it up blue campaign run by Autism Speaks, which is a moderately controversial organisation among the ASD community. So I’m not entirely sure if this is an “I’m supporting Light it up Blue in my own quirky way” message, or an “If Autism Speaks says wear blue, I’m not going to let that stop me wearing red” message. Could go either way.