I'm a live and let live kind of bloke and so think that people should garden in a way that suits them, be it using chemicals, rotavating, no-dig etc. Me personally, I prefer the organic way. I think the use of chemicals relates to what growers ultimately want to achieve and those who want a high success rate will spray to do so. Good for them.
I don't expect or strive for 100% success, I've lost a lot of toms and pots to blight this year and yes it's disappointing when all that hard work results in a diseased crop but then I think of all the successes and that balances things out. For me, owt beats nowt.
I doubt the chemicals used are dangerous to human health but for me, I'd simply prefer they weren't there than were there. Washing off is one thing but when the chemicals hit the soil it's inevitable that some of those will be taken up by the plant, either in that or successive years and as cheap as veg is, if I was going to use chemicals I would save myself a LOT of time and effort just going down the supermarket and buying my veg instead. I also fear that beneficial organisms in the soil could be compromised and that by eliminating pesky pests from the food chain, that the delicate ecosystem of our allotment will be left unbalanced. I'd rather plant flowers that will attract hoverflies etc around my veg to take care of the pests instead.
I grow because I feel a sense of satisfaction in cooking great food using veg I've nurtured myself from seed, and accept that sometimes that will involve some disappointment. Our family doesn't have much money so organic/free range isn't affordable to us, so if we're going to put all this time and effort in, this is the veg we're aiming at.
Enjoy your home-grown veg, chems or not, it tastes better and it's yours. (",)