The worst I've seen was someone blocking entire IP ranges due to fraudulent activity. Once their overall sales started declining, they realized they managed to ban entire university campuses because one fraudsters decided to use the dorm wifi for carding
Especially low margin businesses, where you might have revenue of $20 in a transaction, but a profit margin of just $0.20, fraud is really painful if you lose the complete $19.80. You're happy to turn away a lot of custom to avoid some fraud.
Classic example: Bank loans. They might only earn 1% of the principle, so a fraudster who runs away with the whole principle has to be really rare.
It's also a volume question. If you have low margins but high volumes, you might run a very sophisticated anti-fraud setup to walk the razor thin line around compliant chargeback and refund rates.
From the consumer POV of course it's all the same and annoying at that. But the plumbing behind the system has some insane blunt tools, some programs held together by excel-sheets and duct tape while others are super complex with blackbox rulesets.