Is a social media boycott going to solve racism? No and no one thinks that it is or is saying that.
Is it going to send a message to the likes of Twitter and Facebook that they must do more to limit abuse? Yes - their revenues will drop which is the only way to speak to them.

Abuse and harassment is endemic on social platforms and yes, there are tools such as limiting comments, closing DMs etc but why should those being targeted have to be the ones to take the action? Cut it at the source. Over the years, abuse - racism, misogyny etc - has got worse.

I've been on Twitter (via my personal account) for 12 years and the increase over the past 4-5 years in dick pics, 'nice guys' who just want to say hi then actually take the time to message you to say they hope that you get raped and murdered when you ignore them is staggering.

I know people who have been stalked, doxxed, and been victims of targeted campaigns and the thing is, the reporting tools that exist at the moment just aren't enough. SM companies are happy to collect the revenue but not to invest in teams and policies to make everyone safer.