This person could have corrected you in a much kinder, more informative way! I may have some insight as to why the correction felt important enough to them to point out to you.

We really are trying to push new language when referring to "child porn" and "prostitution."

Child porn is now referred to as Child Sexual Assault Media/material (CSAM). This distinction is important specifically because porn, by definition, requires consent. A child cannot consent, as you rightly pointed out! But rather than rely on another person to be aware of this caveat, were working to make the language more clear.

The linguistic distinction between sex work (prostitution) and human trafficking is extremely important due to the efforts of some to paint them as one and the same.

I'm sorry this person ignored everything else you said. That's a BS way of talking with someone!

But I hope maybe I've shed some light on their reasoning.