if the second star was at 75%, farming bases would become pointless... AND I NEED MY FARMING BASE!
but what would be the point in destroying the town hall if you already got 75%?
Not sure if that is true but if it is,
Noobs could still destroy vulnerable Town Halls and go away with their trophies and loot bonus, defeated players (normally, farmers) would still get their shields.
That update, if it really works in the way described by
@SteelHorse , means that the SECOND star can be achived either by destroing the TH (as usual) OR by destroying 75% of the base.
Again, it has nothing to do with those who destroy THs to get their only star.
@WaLLy
1st star is either 50% or destroyed Town Hall
2nd star used to be 50% + TH, but it might have become either 50% + TH or 75%
3rd star is 100% (obviously, including the TH).
Haven't played for ages so can't be absolutely sure about the update itself => relying on Steel's words