Question: is it okay to attend the wedding of divorced people?
It depends on the situation, especially the reason for the divorces, and how the divorcees view those divorces now.
If both have divorced illegitimately, are still unrepentant, and they can't imagine why you wouldn't come, I would not go.
If the divorces were illegit, but those about to remarry are repentant, and they have tried to reconcile with their spouses, and they are asking you humbly to come, aware of the difficulty, I would probably go.
If the divorces were legit (the other partner was mainly at fault and left), I would go.
This raises the specter of "when is divorce legitimate?" There IS such an animal, but that's for another time. Consider 1 Cor 7:15 and Matt 5:32 for starters.
Lots more could be said, and the circumstance would need to be considered in its details.