I was wondering are olives a type of laxative?

No: There is a long list of benefits from olive leaf extract including anti bacterial, viral, fungal and anti oxidant effect but no study to support it, the only proven effect is on hypertension ( as effective as captopril) and olives don't cause diarrhea but like any other vegetable with fiber , it helps to have a normal bowel movement.

No: If you need a laxative, use a real one. Eat a lot of prunes and you may have a remarkable experience, but olives won't do that.