What Vanellope did was different from Turbo in that she wasn't hiding what she was doing, she wasn't using duplicitous methods to get in, she tried to be mindful not to cause harm, and the characters in the host game gladly welcomed her. Even the first movie showed that visiting another game is not considered that bad as long as you're considerate; they didn't mind Q*bert and other homeless game characters joining Felix's game.
However, the first movie still established that jumping to another game is a risky taboo because it has multiple dangers involved. It causes harm for both your original game (you're abandoning your job and might even render your game unplayable), your target game (you can mess things up for the players like Ralph did), and it's dangerous for yourself too (death is permanent if you die outside your own game).
When Ralph merely complained that he's not content doing his job, all the other characters freaked out and immediately thought he was about to go Turbo. And when Ralph didn't return back to his game, other characters described that as going Turbo. I understood the act of ditching your own game and settling for another as "going Turbo", regardless of intentions.
Ralph got told that he has a responsibility to his duties. The lesson was that even if you hate your job, it's best to suck it up and try to find things that make your life feel worth living anyway.
Vanellope's pep speeches involved "follow your dreams" stuff. They pretty much ignored "Turbo" concerns because it would've shattered their intended message.