What's (probably) incorrect is drawing conclusions based on A without considering the Bs in the population.

Consider: the leading cause of death for young black men is being killed by other black men. Not all young black men! Lots of them are pretty good! Both of those statements are true. What's incorrect is to use it to draw conclusions like "so police should stop and frisk young black men" or "we should avoid endangering the rest of our employees by hiring young black men".

The top-level comment was using age stereotypes to "prove" that an older legislative body is going to misunderstand technology, and therefore produce bad regulation. Showing that the argument was wrong because stereotypes aren't universal, and because in this case there's reason to believe that the samples are selected in a way that would tend to avoid the stereotype, isn't "tone policing". It's directly attacking the argument itself of that parent comment.