They are not the same organization. The sslforfree site is a third-party tool to help you get certificates from Let's Encrypt. There are about 100 such tools, some of which exist as web sites and some of which are installable software or features of other software.
The Let's Encrypt CA has an API to allow requesting certificates, but no web site of its own where you can obtain them from the CA. So, all of these tools are using the API in various ways to help you get certificates from Let's Encrypt.
There's a large community-maintained list at
Most hosts that offer cPanel will have an automated certificate renewal feature—if they don't intentionally disable it! You can also use Certbot (or lots of other options) on a VPS if you have root access and administer the system via the command line, which is not commonly the case for shared hosting.