There are many suggestions to combat hooliganism, many of which can be found in this insightful paper. However, racist abuse is only slightly related to hooliganism, it's not a sport problem per se, it's a societal problem.
The answer is, as always, to be more proactive and have better societal counters to racism as a whole. Truth is, it's socially acceptable to be racist in stadiums, because it's socially acceptable to be racist in society. With the exception of my time in the American South, I've never seen more incidents of racism than when I was in Europe. People were not called out on it, or shamed, or anything else. People just laughed along. Until that changes, these incidents won't disappear.
So, as you propably know, Vinicius Junior been the victim of racist abuse and insult a lot in his career but especially this season in La Liga, there was another case of it in Real Madrid last game against Valencia which took huge proportion. I'm sure you propably already know about this but the whole situation is making a lot of football main actor react and take position.
Anyone has thought on the matter?