I have two questions. If I summon a creature then cast hidden stings, does tapping and untapping the creature remove the summoning sickness?
Is haste the only ability that removes/neutralizes summoning sickness?
Haste is the only thing that can remove summoning sickness, correct.
You are correct. By default all creatures (great and small) have summoning sickness.
Haste is the ability that allows the creature to ignore that rule.
Tapping and untapping a creature will not remove the fact that it still has summoning sickness :)
RESOLVED