@pdavidow
The NetFree filter is not something you install, it is either ISP-based filtering or VPN-ing to a filtered line.
If WSL uses your Windows network settings or is bridged to Windows connection, then it is filtered just like in Windows.
NetFree does provide software for the VPN, but in the end it is just a normal VPN.
However, NetFree also provides a blocking software, called WiFree, which is indeed for Windows only.
This is not an official answer from NetFree