For brick and mortar retail that isn't fast fashion or supermarkets, dropping troublesome customers is generally extremely sensible.

Profit on most goods is low - single digit % typically - and a single return can eliminate the profit margins on a dozen sales. Sometimes cost can be reclaimed from goods providers - i.e. genuinely defective or manufacturer refurbishment programs - and sometimes they can resell the item as new. But if the item has been used, broken by the customer, etc. the loss is significant. It turns out that some people are more honest than others, and some people are directly trying to scam companies.

When one 'dodgy' customer can eliminate the value of 10 'real' sales with every return the maths say to ban people quickly.

A little anecdote - I have a distant relative who, circa 2005, would buy a vacuum cleaner use it, and then return it. He rotated stores (hardware stores, supermarkets, electronic stores) until he gradually got banned from them all. Once that happened he moved house. Not only had he almost certainly spent more in time and fuel than a reasonable vacuum would have cost him (which I will note he could afford); but the cost and waste he has incurred on both individual companies and society at large through that and similar schemes is staggering. I don't know if he's still at it - or alive - but the people he was surrounding himself with all saw such behaviour as reasonable.