Most likely these sites have not reviewed the project yet. Many projects in the early stage have little or no publicity, so not are picked up by these sites. But beware that even if the project is listed doesn't mean it is all good, case in mind Benebit, rated above 4 on icobench, but turns out to be scam.
If the project is just gaining popularity or just started, then it may not be added yet. Although sometimes it turns out that well-known projects are added to the ico bench at the end of the sale of the tokens. So it turned out for example with CryCash.