I don't see what GP did as much different than how most recruitment processes work from the hiring side. You usually don't find out:

  - salary
  - stock options
  - contractual terms, like non-competes 
  - etc

until you have cleared their hiring bars first.

I'd love to see full transparency on both sides, but until we do I don't think they did anything wrong, and in fact just applied the same approach used by many companies, waiting until they were committed before making their big ask.