No... Lots of people see lots of reasons NOT to.
But I believe the reason it's common to max-tune is because of the way online racing is...
In online racing, there's no way to force-restrict individual tuning parts for an online race. You can restrict hp or pp - but people can always power limit the car into the restriction. If you set up an organized race, & restrict tuning parts out, it's more or less an honour system. This honour system would never work in pub lobbies or in races that are not closely monitored for signs of cheating. (And that's a lot more work than most people have the time and/or patience to do.) So most races nobody bothers to even try to restrict parts. So that means everyone buys all the best parts on cars they plan to use for online racing, then power restricts down to whatever hp or pp... If you don't add all the best parts, chances are you're not going to be competitive, even against the same exact car. Simple as that. And since people find they could be faster if they use lots of tuning parts, it forces everyone to use lots of tuning parts to be competitive.
So it's a culture that's evolved out of a fundamental issue of online racing restriction capabilities.
It happens in every online multiplayer game basically. There's something that can give you an edge... so people start doing it to get an edge... Then everyone has to use it if they want a chance at competing.
That said, MANY people think less tuned cars are more fun to race.
It's probably why public lobby
shuffle races fill up fast.
Also, I have to say, I don't know why every thread has to turn into a debate about what tire types other people are using for whatever cars. Since at least
tire type is something you CAN restrict in an online race. If there were no tire restrictions, and everyone was forced to use racing softs if they wanted to do any online racing... well then I could see getting bent out of shape. But there's plenty of races that have restrictions on tire types.
And no matter what you do, once you change tire types, it's inevitable you might have to adjust the tuning a tad, to suit the tires & purposes. Even if someone posts a tune that's on sports soft... if I'm going to use the set-up on sports hard, I have to adjust it sometimes. Sometimes set-ups have to be tinkered with for different tracks. And anyway, a set-up one person might like, and one might not, for various reasons of personal driving tendencies. It's not like you can just say oh - well I'll tune it on comfort hard or sports medium or whatever, and then that'll be good for all tires in all situations for everyone. There's no one-size-fits-all tune anyway.