I think any kind of chain pet store and even local pet stores to an extent can be very risky regardless
It is unfortunate,but sadly there just isn't the same careful breeding that is necessary for high quality healthy animals from a chain pet store or even quite a few local pet stores(I know I've heard of local pet stores selling puppies from mills and things like that).Even then some hamsters can be from the same sources but still be much healthier,as lots of people have experienced!
There's definitely a lot of variation with individual chain pet stores,so the only thing I can suggest for anyone is to really be aware of the individual animals and if they seem healthy or not and things like that.It's ultimately a personal choice whether you purchase from pet stores or not,but in this case the pet store in question definitely seems like a very bad one