You’re right, it’s not about unity. It’s about people protesting to make themselves feel better instead of actually doing something to address the problem.
People who already agreed with his stance before the protest say it’s successful because people are talking about it. The problem is, the “it” they are talking about is the protest, not the issue of racial injustice.
Not a single person saw him or any other player sitting or kneeling and said “gosh, I guess there really is a racial injustice problem after all!”