Earlier quoted context omitted.
The racism comes from saying "We recognise human faces" and then not recognising a significant proportion of humans.
That's not racism, that's laziness. Or perhaps just being a bad engineer, if you want to be more cynical about it. It's not that hard to find both conscious and subconscious examples of systemic or individual racism. Engineers taking the easy path with webcam facial recognition is probably not a good one and serves only to give more fuel to those who claim people jump to the racism cry too quickly.
Personally, I think it could be understandable people didn't consider race when developing facial recognition technology, especially when we've only had mainstream awareness of this for under a decade and many people live in racially homogeneous or dominated cultures. However, I don't think it's acceptable for organizations, and the time when you can safely say you didn't understand biased learning data will be over soon. There are considerations you need to make scaling your tech from personal project to something the public will consume.
Also, the day will come when computers can point out racist stuff better than the average human can now, albeit with a high false positive rate. I say this because it's relatively easy; even if you only count a subset of tweets talking about racism as not trolling, that's still a shockingly high number of meaningful things about the world many people aren't seeing.