PG is more harmful. It can be toxic if you consume 1 liter of it in less than 30 minutes. That is if ingested. there is not much studies done on effects when inhaled. I try to stick to high VG juice as much as I can just for precaution.
You're suppose to vape it not drink it.
As for more harmful, I would be interested to see your research or links to research that show this.
As has already been mentioned, PG is used in medical inhalers and actually is probably the most understood ingredient that we inhale in our e-liquids.
Just because the word vegetable is in VG doesn't mean it's necessarily better for us