So I'm curious about the Worms and if they could even be a positive thing, besides how nasty they "seem to be."
Worms in food is never a positive thing. There is just no positive way to spin it. Something like this, natural or not, can potentially be a restaurant killer, especially if the establishment centers its business around seafood.
I agree with one of the posters that worms in oysters are a sign the oysters are incredibly fresh. Hence, the importance of a good, experienced shucker. When I was a kid, we used to knock the oysters from the peer with a hammer at low tide and sell them for a nickel a piece to whomever would buy them. When we cleaned them, we removed any young plant growth, algae or hitchhikers such as barnacles. It was hard work and I still have the scars on my hands to prove it. Occasionally, we ran into something that was just plain terrifying! lol.
Restaurants do not pay shuckers very well and the farther away you go from the coasts, the harder it is to find someone who really knows how to properly shuck an oyster. Here in the Midwest, there are very few establishments (and by "very few" I mean rare) that will serve raw oysters. A few high end places might serve oysters on the half shell. Obviously, geographic location is a bit of a concern. However, there are restaurants all over the this area that serve fresh seafood, as in caught that day, fresh. Its one of the benefits of being within a 2 hour flight of every coast in the US (except Alaska, of course). Despite the relatively common fresh seafood joints in the area, very few will touch fresh oysters precisely because of the so called "risk" that is complicated by the scarcity of those who know how to properly shuck an oyster. There is so much that can go wrong between when the oyster is harvested and when it reaches the plate, that most chefs figure its just not worth the risk.
Anytime I see oysters on the menu out here, one of two things is likely at hand. 1) They're crazy or don't know better or 2) the chef has had experience with oysters and knows what he's doing. A few well placed questions to the server about the chef and the oysters will usually reveal which one of these possibilities is likely to be true.
So, basically, worms in oysters, especially farmed oysters, are common, normal and expected. Despite the level of gross that goes along with their presence, they are not a sign the oyster is "diseased" or unfit for consumption once the worm has been removed. But, it is definitely one of those things that must never ever be allowed to leave the BOH....ever. Like I said, something like that is a potential ice berg for an establishment.