In Sweden (the home of Klarna) you've been able to pay for your DoorDash equivalent using Klarna for ages now, and I've never heard of any backlash or even anybody questioning it. If you can pay by credit card, why not Klarna? I'm surprised that in the US, the credit card Mecca of the world, this even moves the needle.

edit: In fact if I was more conspiratorial, I might suggest that this 'backlash' was orchestrated behind the scenes by Master Card and Visa to protect their market share.