My guess is that the City Attorney has been heavily involved in this decision. The articles I've read have alluded to the city likely losing this battle in court. I'm not sure they want to spend the money fighting this - and I can't blame them.
That could be the case, but it is odd that the staff report never mentions advice it received from the City Attorney's office. Staff also never mentioned discussions with the City Attorney's office in their presentation.
I don't know all the rules, but is the City Attorney's office allowed to provide guidance to quasi judicial bodies like the Zoning Board of Adjustment and Zoning & Planning Committee? I thought they had independence and indeed have enumerated powers under the City Charter. So even if they can receive guidance, they don't have to follow it because they are supposed to make their own determination.
As far as fighting it in court, right is right and wrong is wrong. I've looked at the case law myself, and Burger King does not have a great argument. It is mediocre, at best. For the City to not want to fight to defend a unanimous decision of one body, as well as the findings of City Staff, is really pathetic from my vantage point.