Unfortunately that site does not guarantee Pi-hole compatibility, either.
For example, from https://github.com/cbuijs/accomplist/blob/master/chris/regex.black I tried to add
^(.*\.)*(adult|porn|sex|sexy|xxx)$
to Pi-hole but got an error ("Wrong token") although it was accepted on that test site.
EDIT: I added
\.(adult|porn|sex|sexy|xxx)$
instead but that was not my point.