I followed the link and read the actual complaint. A couple of the claims may have merit, if they are true. One, equal protection, says that the city has similar sweetheart deals with other organizations who discriminate in some way or another, but the city is not trying to evict anybody but the BSA. Another is that over the years, the BSA built and paid for the building in question, even though it was built on city land. If they're evicted, they want compensation for the value of the building. The third alleges that the city's offer to charge rent is actually punishment because the rent they're asking is (so they claim) twice the prevailing price per square foot for prime office space.

Like most things, that this particular action by the city isn't entirely black and white. Depending on the judge and the jury (they're demanding a jury trial), the lawsuit may have some legs.

By the way, I agree entirely that the discrimination policies of the BSA are reprehensible. Nonetheless, we live in a country where even scoundrels are entitled to due process.