The only way to stop this would be for 23andme to monitor these "hack lists"

Unfortunately, from the information that I've seen, the hack lists didn't have these credentials. HIBP is the most popular one and it's claimed that the database used for these wasn't posted publicly but was instead sold on the dark web. I'm sure there's some overlap with previous lists if people used the same passwords but the specific dataset in this case wasn't made public like others.