And for that I reference you to the second part of my comment. It is highly unlikely that a highly reviewed, frequently reviewed charger on Amazon will light your phone on fire. As for the second point "what if there is no reviews?" Simply don't buy a charger that doesn't have reviews.
If every charger sold lit users phones on fire they wouldn't be in business for long. The dangerous chargers generally have bad QA and inadequate insulation and separation between the mains and output, so almost all of them will work at first but a few will do nasty things like dumping 120V on the output, either immediately or some time later after the insulation abrades or dirt bridges the gap.
Are you confident enough that a seller who is willing to sell counterfeit chargers is always going to send the same exact counterfeit chargers? I'm not.
No. I am confident enough that if something has over x number of 5 star reviews (500, 1000, whatever makes you feel confident), the statistical likelihood that I will have a bad experience is small.
...or when the fake charger you unknowingly received catches fire or ruins your phone?