I know it really is! Especially the PVP - that's in almost every good curly hair gel and conditioner as it seems to help curls a lot.
Napiers used to do a gorgeous conditioner that was only cetyl alcohol and essential oils and seaweed extract. Nothing else at all. It smelled delicious too. I've got half a bottle left and I'm slowly working my way through it now. But then they discontinued it and brought out a new range of conditioners, with another company Culpepper. The are almost the same ingredients wise APART from the fact they've all got 2 of the nasty preservatives. WHY?! The other one works great and I've had it for 6 months and it's not gone mouldy on me. I have no allergies with it all either. No sneezing, no itchy scalp. I would so buy these new conditioners despite the £2 price rise if they didn't have those preservatives. Sigh.
I'd love to do a Jessicurl myself but the market is becoming SO competitive as curly hair is becoming popular. And i've yet to work out exactly what makes my hair nice so I'd be a bit of a loss Plus I have weird hair that is fine so is overconditioned easily but is 3b and big so needs moisture to combat frizz. I don't think my products would work for many other people hehe.
Really, you shouldn't let that website get you too worried. They are trying to sell their products by making you paranoid.
Mineral oil is actually very inert and has an extremely low tendency to cause skin reactions. If you read their caution about PVP, they are saying that droplets might cause lung problems. Even if this were valid scientifically, which I doubt, you are not spritzing it into your lungs when you use hair gel.