Gambling online isn't illegal in the US, the new legislation targeted gambling businesses and banks. In other words, it really does nothing.
It makes it illegal for a gambling business to accept an online wager and it makes it illegal for a bank/credit card company to process a request to fund a wagering account. But it doesn't do anything to the individual gambler. And, if you're wagering on horse racing none of this applies in any case, only for other games of chance (poker primarily).
ripley.