I am not an expert on Adobe's strategy for protecting their digital rights but I know that it is arcane. I am betting the two installed copies of Photoshop are both on your computer. Possibly one copy on your regular hard drive and another on a clone drive (assuming you have one), or if you have installed a new hard drive and restored Photoshop from a backup Adobe is seeing the new drive as a new machine, or Adobe thinks the Photoshop installation on your HD is on a different machine because you have upgraded your OS X version. Or some variation on one of those scenarios. I suspect a call to Adobe tech support can clear up the problem.
Hackers are generally not interested in stealing your software, they are primarily focused on obtaining items of real value such as your name, social security number, date of birth, etc. With that information they have all they need to steal your identity, open credit cards and charge accounts, take out loans, mortgage your house, and leave you holding the bag. If they can get your bank account numbers along with the other information they can withdraw all your money from the bank, max out your credit cards, and in general leave you penniless. Don't be fooled into thinking the police can or will be able to help you — they can't and won't. The police agencies that are capable of tracking and prosecuting these felons can be counted on the fingers of one hand and all too often the thief that steals your data lives and works in a country that has no extradition to the U.S. or Canada. That person then sells your data to yet another person, or persons, who then use your data to steal your money, your property, your credit rating, and your good name.
