do not run the installer directly as/from the 'root' account! Always use the sudo command from a non-privileged user account. This is due to variables that are different between root's environment and a user's that aren't affected by an EUID change, as well as code checks in the install itself.

sudo, especially combined with NOPASSWD as recommended in the comments, has no security benefits over just using the root account.

Now using sudo to work around the root account is not only pointless, it's also dangerous: at first glance rsyncuser looks like an ordinary unprivileged account. But as I've already explained, it would be very easy for an attacker to gain full root access if he had already gained rsyncuser access. So essentially, you now have an additional root account that doesn't look like a root account at all, which is not a good thing.

No, clumsily working around the root account in situations where it is absolutely appropriate to use it is not for good reasons. This is just another form of cargo cult programming - you don't really understand the concept behind sudo vs root, you just blindly apply the belief "root is bad, sudo is good" because you've read that somewhere.