I'm sure a rich white billionaire is sitting there thinking "hmmmm, let's look at all of the t-shirts this guy has worn in his life before we sign him to a contract and try and win football games".
and it was also a Malcolm X shirt that featured Castro, Kaep wore numerous Malcolm X shirts during said time period. If you asked 100 people in Miami about a possibly offensive t-shirt Kaepernick might have worn over a year ago, would even one person know about it? You bring it up and you didn't even get the correct person on the shirt right until you googled it a few minutes later lol
But once again, I highly doubt the billionaire that owns the Dolphins gives a shit about his t-shirt. They only care about all the redneck white people who are mad over the National Anthem.