But it does in a way "ruin" the system when you have others who are generally healthy, but who milk from the system simply because they've found a way to do so. It undermines the intent of the system, as it was established. It's a form of fraud.
It's sub-optimal, which I wouldn't call 'ruining'. Neither fraudulent insurance claims nor denials of legitimate claims 'ruin' the insurance industry, for example. Neither is desirable, but their existence doesn't condemn the industry as a whole.