Do I understand this correctly about a Level 1 Druid in 5e
with Wisdom modifier of zero, s/he can only prepare 1 spell despite having 2 slots from which to cast ?
Druid spell preparation is determined by their Wisdom modifier plus spell level:
You prepare the list of druid spells that are available for you to cast, choosing from the druid spell list. When you do so, choose a number of druid spells equal to your Wisdom modifier + your druid level (minimum of one spell). The spells must be of a level for which you have spell slots.
In your case, you have: WisMod(0)+Level(1)=1
Wisdom is the primary stat for a Druid. Having a suboptimal Wisdom is a choice, but this is a consequence of that choice.
Yes your wisdom and experience level let you prepare only 1 spell, which you can cast twice besides your cantrips which are at will. Even better if you were to choose a spell with a ritual tag you could spend 10 minutes plus the casting time and cast infinite times, saving the 2 spell slots for a rapid cast. Per the PHB.