delayed by car because of traffic is much higher… but nobody complains about that
Because if you are running into a car delay, it is your fault - you made the decision to take a congested route or not re-route before an obstacle sudenly appeared.
When you travel by train, you give up some control over how that travel goes, thus, if shit goes tits up, people will complain about the operator fucking up.
People might argue "you also made the decision to use DB to travel!", but it's only valid a short while, since using a third party to travel, you trust them to hold up their end of the deal, relinquishing control and responsibility.
If I'm in control of a car and making the choice to take a route, this is all on me. Sure, I can "curse" the idiots causing delays, but it still comes down to me.