Yes, there is the “or lose it” option. There is no forcing. They have the option. I can understand that they don’t like the rule. But to say they are forced is like saying your friends forced you to to go to a movie with them. It’s not forcing in any way.
That option is to lose their slot, if they lose their slots, they will probably lose an entire hub on their network that they can not regain.
It's not like you can just buy these slots back. In fact, slots are valuable for the simple reason that they can not be bought and sold. (unless airlines consolidate, and even then these transactions are heavily scrutinized)
You're basically saying it is better for them to tank their business so another airline can steal the slots from them.
And do you know what the competition will do? They will keep that slot at all cost regardless of whether their planes are full or not, because this is how airlines maintain their network.
Please consider familiarizing yourself with airline network operations before speaking authoritatively on the subject.
I’m well aware. It’s still their choice. It is absolutely a choice for them to behave this way. Why would any of us take the side of Lufthansa over the side of another airline? Possibly one that is actually flying passengers around? I’d respect them more if they said “we actually believe it’s a stupid idea to burn fuel pointlessly, we’ll take the side of the world’s good over our own medium-term interests”.
“Inspiring” is probably the right word.