Hard to opine on whether it's a systemic culture issue based on just sporadic incidents that occurred out of numerous flights flown daily by visible Jews, chassidim in particular. LH is the default carrier by most European mekomos hakdoshim trip arrangers. I've flown with LH a few times and only had great experiences. That does not say that AS isn't abundantly prevalent in Europe, plus the rigid adhering to rules they expect, which will inevitably be reflected in the attitude of some employees. Perhaps LH can do a better job at curbing that and should be called out and held accountable for their crew's misbehavior, but that hardly earns them a nazi airline title.
There are other antisemites in the world, but what earns them the Nazi airline title is this little known fact that they were literally the Nazis airline (even before they were in power) and voluntarily created labor camps and deportations to concentration camps.
To this day they deny their Nazi history because they formed a new legal entity using the same Nazi supporting staff.
A Nazi doesn’t stop being called a Nazi because the war ended. Their kids and grandkids are running the airline, and they still tacitly accept neo-Nazis in their ranks.
The bar really isn’t that high for them to get rid of that moniker, but they’ve repeatedly decided that have no interest in that.