Our defence is not rubbish, and the constant exaggerations don't help discussion.
But there are issues. We do have shaky personnel at the back. We should be conceding under 20 goals a season with the system we have. Sometimes in fairness it's as solid as it needs to be (hence all the clean sheets) but it has a habit of dropping a bollock and sometimes this past season it's struggled against better attacks. If you look back at all the goals we conceded this season I reckon a lot come down to bad pieces of defending by at least one player.
To repeat our defence obviously isn't bad but it's certainly incomplete. Really I think another CB with a bit of leadership plugs almost all the problems. I do think it's that simple. Our defence becomes significantly less porous almost immediately.
Another thing is that I think with our system the xG conceded should be lower, as impressive as it's been. The way we play would cause even the most defensively excellent back line ever issues. That probably stems from worse pressing up top, but I'd argue that THAT stems from Pep not trusting the defence.
Basically, we're better defensively than people say we are, certainly as a team. But there's improvements to be made and the most obvious fix is in the CB department.