I'm not sure about hiding it fully, but if you don't want others to know what manga you have on your lists you can specify that when you add one to your lists. Just check the "only visible for myself" box instead of the "share to timeline" one, which is automatically checked. I've been doing it this way for years so only the first 10% of my lists from before I started doing this are actually viewable for other people :p

can everyone see our own already read/want to read/reading list? if they can, can i hide it the list?