From what I understood in the tweet they posted, the issue was the use of third-party software compatible with Ledger that didn't support Clear Signing.
I don't trust anything coming from ledger anymore, including that twitter post.
They twisted truth many times to fit their agenda, and they are making crap devices.
Blind or Clear Signing or not, it was a user error.
This is like saying soldier should be blamed because his rifle didn't do what it was designed to do.
Sure, soldier is responsible for using a bad rifle (aka ledger), and he was not very smart, but item he used had manufacturing flaw.
And blind signing is not industry-wide problem, it's only happening with some wallets.