Several of them are.  Some aren't, such as icoalert.com.

There are many sites that list ICOs and token sales.  However, they are a subset of the list on Bitcointalk.org's Announcement (Altcoins) page, for the following reasons:

• Not all of the project teams will know about all of the ICO sites, but they all know about and will announce on Bitcointalk.org's Announcement (Altcoins) page
  
• Not all of the projects will pay to get listed on these ICO sites

However, Bitcointalk.org's Announcement (Altcoins) sorts the announcements based on which ones had the most recent comments.  Therefore, on the first page, you'll see announcements that were originally posted months ago and even announcements whose token sales have ended.

To find the most recent announcements, go to Bitcointalk's advanced search page and enter:

• ANN in the "Search for:" field
  
• Change the "Between 0 and 9999 days" field
  
• Under "Choose a board to search in, or search all", uncheck "Check all".  Then click on + to expand the list and check only "Announcements (Altcoins)"
  
• Click Search

This will show the announcements for the days that you selected.