Not sure about "all", but apart from that article being more pissy than strictly necessary, RAID1 can now, in fact survive losing ore than one disk. That is, provided you use RAID1C3 or C4 (which keeps 3 or 4 copies, rather than the default 2). Also, not really sure how RAID1 not surviving >1 disk failure is a slight against btrfs, I think most filesystems would have issues there...

As for the rest of the article — the tone rubs me the wrong way, and somehow considering a FS shit because you couldn't be bothered to use the correct commands (the scrub vs balance ranty bit) doesn't instill confidence in me that the article is written in good faith.

I believe the writer's biggest hangup/footgunnage with btrfs is still there: it's not zfs. Ymmv.