Look at this from their point of view, not yours. Most people have this understanding that lawyers are expensive and Zillow is a big company, it is natural and

Look at this from their point of view, not yours. Most people have this understanding that lawyers are expensive and Zillow is a big company, it is natural and reasonable to expect that fighting or resisting Zillow is going to be expensive and it is better to shut down first and find out what to do next. You're also making a huge assumption that even if the lawyers agree it is BS, Zillow would not pursue this matter further, causing them to retain a lawyer that will require money.