You cannot disable ipV6 from the web console, despite what it suggests, but you can disable it from the server console, or via the shell. Here we'll discuss the shell method since that's the most commonly used.

Firstly enable SSH and SHELL if not already done so.

Now ssh into the vmware box and use the following command

esxcli network ip set --ipv6-enabled=false

And that's it, now reboot the host (making sure to shutdown all the VM's first) and there will be no more IP6.