The key though is this operation only happens when it’s part of a requested credit evaluation for the purposes of expanding credit. The act of requesting new credit diminishes your credit worthiness. The intent is to throttle issuance of credit by providing for a race condition - if I go out and apply for 100 credit cards at the same time, they each get a credit report without the others line of credit established because they’re all in the pending state. But each request to evaluate the worthiness of credit dampens the quality of credit. At a certain point all credit requests thereafter fail.

On the flip side it also causes a hole that’s increasingly hard to dig out of because if you have bad credit or borderline credit and apply for a card to see if you’re allowed back in at the capitalist buffet, you enter into a feedback loop of diminishing credit worthiness.

It isn’t true however that any form of read changes credit worthiness. There are many routine reads that have no impact. It’s specifically when you’ve directly requested an evaluation for expanded credit. It can’t happen passively, as sometimes banks refresh your credit history and even offer more credit automatically. It also can’t happen for other purposes than expansion of credit.