The thing with this issue is, that every phone has their issues, such as the Apple IOS update a while back that bricked people's phones, people just wiped it off. It just seems all of the Non-Samsung fanboys are just hating on them as the Samsung vs Apple war carries on, each phones have their positives and negatives, and everyone has their own opinion. People like the iPhone series due to the well optimized processors, and people like the Samsung series for the cameras. There's many things that Apple and Samsung are on par with, and many things they aren't.
As said above, there have been Apple phones catching fire, such as that one person who received it DOA after it had caught fire or exploded in the delivery process. Nowadays, the battle between the phone companies are putting some insane pressure on them, and they release phones without complete testing for any issues such as this, just for them to release a phone.
I am not exactly a fan of any phone company, I prefer Samsung as I like the speed of the processes, the functionality and the design, I admit that Apple phones are probably, in some case quicker and look really nice, but to be honest, it's just a phone.
And also with the designs needing more optimization and speed increases to keep the customers coming, there will be a heat increase as well, a larger battery, just to keep the phone going and being under great recommendation by the fan base of that phone. All phone companies have their issues, and it just seems that Apple seem to go under the radar when they have issues.
But you must admit, Samsung is taking it in the right step, showing that they care about the customers of their phones and admitting their mistakes and resolving them as soon as possible to get their phones tested, optimized and known as safe to use for their customers.
The 'Exploding Phone' issue isn't 'Just' Samsung, its every phone company, there probably isn't a company that sells phones in the current age that hasn't had some sort of overheating phone, may it be the battery, processor, LCD, or any other component of the phone. Every company has their issues, and the amount of pressure from the customers and the press, they might rush things a little.
And it wont be just phones, it'll be Laptops, Desktops, Tablets etc.