No one can speak meaningfully and reasonably about anything on social media, let alone the politics of racism.
The medium makes the message almost completely devoid of meaning.
Seriously, there is no problem with the operating definition of racism outside of social media.
Every idiot screaming about the alt-right (or their phantasmagorical counter-part, the social justice warrior) is just someone who spends too much time on Twitter.
Might as well be complaining about what policies the Orc players in WoW use to justify who they vote for.