@Bonnie416 Taking it personally? No. Not sure what gave you that impression.
Two wrongs don't make a right, do they?
Of course the host should have sent check-in info, but as most hosts don't send that info until a day or two before check-in anyway, how would that have changed the fact that you booked the wrong dates and were not eligible for a refund? Even if he had sent it the day before, you still wouldn't have been eligible for a refund.
If the host said he never sends check-in info, that info must have been included on your reservation, no? Or in a message when you first booked? Or in the listing info? How else would any of his guests be able to access the place? Sounds strange. Is he a new, clueless host, maybe?
I'm not sure how you consider that asking for a refund, or to apply your payment to a rescheduled booking, after your booking dates had come and gone, is "owning the mistake". Had the host refunded you, that would have meant he was deprived of his income for dates that weren't open to anyone else to book.
Owning one's mistake means accepting the consequences, not trying to blame someone else because they weren't as responsible as you expected.
You getting your dates wrong and not realizing until the dates were over is a separate issue from the host's lack of communication.