I tried that, and it didn't work.
I've been working with Linux since the mid 90s, so I know how it sudo should work.
Again the point is, I should have to go through this. I'm running CentOS and it works just fine.
That's odd, I'm running a flavor of Ubuntu (Mint) as I type this and it just worked perfectly for me...
Well you have a setup that you're happy with now, so that's what's really important.
Just FYI, Mint gives you the option to create a root account, so if you want to be able to login as root that's another way to go.