Why couldn't this be "will be destroying"?
because you would need one of the continuous forms to specify, such as 'er vi ved at ødelægge', 'vi star og ødelægger', 'er vi i gang med at ødelægge'.
Hvorfor "..we are going to..." er forkert?
why can I not say: the house of the badger
It is called a set in english even if Danes think badgers live in houses!
Why not "tomorrow will we destroy..."?
That's not the correct word order in English (I am Native English Speaker)
Rather, "tomorrow we will destroy..."
No animal lovers in Denmark? People are very good at destroying nature.