Comment by wongarsu

Many homosexuals are visually identifiable as such (with reasonable certainty), some by accident and some by deliberate signalling. I can easily see how the absence of any such signals could end up as a classification as heterosexual, even though it really should put them in the "unknown" category.

Of course any automated classification of that kind quickly gets problematic in multiple ways. In the EU it's a fast-track to getting your AI labeled as a "high risk AI system" that has higher requirements for quality control, ensuring fairness and user choice, etc