Even an Apple charger can damage a Mac. It's far, far more rare since Apple tends to have superior QA and more motivation to make sure the adapter fails safely and fails before the computer would than the average knock off manufacturer is motivated by safety or adding cost for a margin of safety.

That being said, there are many good chargers that will work just fine. The main risk is fire from a poorly constructed transformer as opposed to down stream damage to your Mac since the magsafe port delivers between 3 V and 25 V DC it's not a huge amount of power or danger to life or hardware.