The publisher of course won't be doing books that are over 100 years old but if there was real demand professors could go to these sort of open publish sites and write their own reviews. That fact that they don't leads me to believe the demand is more about celebrating victimhood than actually solving the issue.
I did try a couple of more well known classics like War and Peace and Brave New World and they are there but you right that the site does focus on books that would be attractive to K-12 readers.
Good reads does have a trigger warning section but I couldn't tell what the trigger was for.