This is not the case, strictly speaking. It instead results from people perceiving there to be a lower bar for diversity hires; whether or not it is rational to describe things in that manner based on empirical data or what not is ultimately inconsequential. In that context, it is entirely possible for a poorly formulated memo to cause this type of damage, and likewise entirely possible for this perception to be perpetuated if institutions like Google do not properly back up its practices with compelling arguments to people who might otherwise have doubts.