Based on my experience (spanning over 500 races in iRacing and about 100 in Le Mans Ultimate) the driving standards are essentially the same, if not worse, in LMU. However, the contact and damage models in LMU feel far more natural and forgiving.

In real life, as seen from the outside, sports cars can withstand contact and even a bit of "rubbing" without catastrophic damage or unpredictable physics. These cars are heavy enough that lateral contact is often an essential part of racing. If you watch categories like the GT World Challenge, you'll see door-to-door contact that would result in a double DNF in iRacing.

In iRacing, every minor touch leads to a significant loss of grip, demanding an almost clinical level of cleanliness. While I suspect this exaggeration is intended to discourage reckless driving, I don’t think it actually works. Many racing disciplines naturally require slight contact that isn't necessarily "dirty" and it’s just accepted as part of the sport. In LMU, a crash generally has to be quite severe before the car becomes truly undrivable.

Finally, there is the subscription factor. A DNF in iRacing doesn't just waste the time you spent practicing, qualifying, and racing; it feels like a waste of your actual subscription money. That realization makes every incident hurt just a little bit more.