lately, it seems like everytime there is a discussion about a byb's website, that a YT member runs off to tell the person about it

Not that it matters really...I think whether we know the breeder is reading or not, members will still be honest.
To the breeder - it is never okay to breed a 3lb female. And sire size (as well as the females size) are not the only factors to determine when breeding the two together. Talk to some of the reputable show breeders on here..they'll tell you that you can breed a larger male to a smaller female. It's important to know the sizes of all the dogs in the mother and father's pedigrees and whether or not the females were free-whelpers. You're lucky none of your girls have had to have a c-section, but breeding a 3lb female is just too dangerous. Also, why bring tiny yorkies into this world on purpose? Even if they are healthy, their safety will always be in question. There are so many more dangers for a tiny yorkie than one that is say 5-7lbs. It's just too easy for a tiny yorkie to fall of of something, break it's leg, get stepped on, etc.
Are you at all familiar with the YTCA's code of ethics? They state that most females need to be at least 5lbs to be bred.
Also, I'm just never okay with someone who uses dogs (or cats) to make their money. Breeding as a business is very wrong in my opinion. It's not fair for dogs to be living their lives in kennels with little human contact with their only real purpose being to breed and produce a profit for the breeder. I don't understand how anyone can be okay with making their living off of breeding dogs