It's kind of ironic that you invoke context, yet conveniently ignore hundreds of years of context of that symbol and idea being negatively associated with black people. Are we doing context or not? You can't pick and choose and then be surprised when people minds immediately go to the centuries-old practice rather than the newfangled text speak, which is a notoriously unclear medium of communication anyway.
No, this is a straw man and no one is suggesting that. Still, it's best avoided and he shouldn't be complaining about any punishment coming his way. He needs to be smarter.
I don't think he intended it either. But for certain measures a strict liability approach is taken to avoid and/or stamp out the questionable behavior. You can debate whether it is warranted in this context or not.
To take it out of a race context, the idiot United support who wore that "97 Not Enough" shirt, was also treated with strict liability. I myself thought he was referring to their 97-point season in which they failed to win the title, because I had always associated the Hillsborough disaster with 96.