They have to appeal to a wider audience obviously. That comes down to messaging as well. But what Yang seems to be obsessed about is making white people happy by not focusing on social issues like racial inequality. Ok now you're hedging your bets on hopefully appealing to the "working class" (we know what this is code for) at the risk of losing big urban turnout. It's counterintuitive.
If Biden decided he wasn't gonna address the racial divide in this country, Biden is more likely to lose in these states where the urban turnout/disparity was greatly in his favor. Yeah Trump was gonna lose that vote but who knows if it would've been by this margin. You can put a focus on both, which I honestly think is what Biden did, instead of outright ignoring the other.
Maybe I'm hearing Yang wrong but I see other people are picking up on this.