Yeah I hear what you're saying. However, I still don't think it would be considered genocide in the conventional sense because the woman is not being compelled to have an abortion, it is an individual choice.
Even if the percentage of women electing to have an abortion is high, they're not acting as a singular cohesive body with the collective goal to eliminate all children having Down syndrome.
How many children do you have? For each of ours, there is a strong push for early genetic testing from everyone, primary care, OBs, friends and family. For our first, they were flagged in an ultrasound and they asked whether we wanted to terminate (kiddo ended up without down's, even the Harmony test is only 80% accurate among high risk mothers). The manner in which the "choice" is presented is heavily biased at a systemic level.
Even if the percentage of women electing to have an abortion is high, they're not acting as a singular cohesive body with the collective goal to eliminate all children having Down syndrome.