Hence, the two big Occasions(Festivals) have been bestowed on us by ALmitghty to Gain the spiritual happiness by taking care of the poor and needy and the neighbours etc. etc...
these cannot be harmful to Humanity at all.
Had it been harmful to humanity then Almighty had not bestowed them to us.
BTW the sufferings are nothing but caused to self by negligence and greed and carelessness of humans only.