Biting happens. I know how painful it is as a parent. I've been the parent of the child bit and the provider having to address both parents. I don't want to minimize what you are going through or what your son is going through. It's true that they remember this. My 10 year old still talks about a little girl that bit her several times when she was 4 years old.
BUT...and there always is one isn't there?
You can NOT ensure a biting free daycare. NOTHING we do can stop it completely. Once we know a certain child is given to bite we can work harder with that child. But they can do it so fast that it still will happen. If we let them go they will bite others in the new daycare.
I have a child in care now that has bit a few times in the last year. We've been VERY fortunate that the behavior hasn't spread. The times he did it were to children that were old enough they didn't respond in kind. But usually it's one toddler to another and the toddler getting bit is now a biter. Wait to see how you feel when your the parent and your child is doing the biting. Feeling bad happens but that doesn't change it either!
I would like to add that as a provider I try hard not to get myself into that situation if possible. I had a child bite someone during an interview one day. I didn't accept the child because I had not had an incident in a few years and I was so hoping it wouldn't start a new round.
I would NOT want to take on your child right now either. Your child is highly likely to start biting and soon. It's not fair, but it's the way it is.
But the flip side is that I will not let a child go once they are already in my care because I don't want to knowingly send that child onto another daycare when there's a good chance they haven't had an incident for a long time.
When I said that we can't guarantee a bite free daycare, I didn't mean to say that biting ALWAYS happens. I've seen as many as 5 years go by without a biting incident. It's the luck of the draw. I've been in business 25 years. Mostly it's not even as big as a problem as hitting or pushing and parents usually don't freak out about those things. By far the parents in these situations are the main reason for so much stress. Providers are between a rock and a hard place. I think your anger is misplaced and over the top.
If you do research you will likely be even more upset. You can find all kinds of horror stories out there to focus in on. Sometimes kids get bit repeatedly in the SAME day. I know for a FACT that they can be bit and not say anything or say it laughing and or not cry so that if the provider doesn't do a strip search they think the child was playing.
I can also say that Many, MANY bites never get reported because they don't even bruise or show marks. I've seen many kids bite a finger and it's red for like 10 minutes. I don't even consider those biting incidents. It's AGE appropriate despite being unacceptable.