The problem with the 50 is that it has had multiple problems. Fixing the connection may prevent one issue (them catching on fire while charging) but doesn't fix the "auto-fire" issue, nor several of the other issues that have come about.
Yes, some people have 50's that work perfectly fine. But a lot of others have not had the same luck.
I think many people see the 20, 30, and 50 and think "Why not go for the 50", but in fact the 20 and 30 have not had the problems that the 50 has, and I believe it's a matter of pushing the technology beyond it's limits. (For the auto-firing, I think their MOSFET can't handle the higher power reliably, and some significant percentage of them fail).
It isn't a matter of hating, just a matter of warning people. And the failure modes are NOT benign, these can pose a real danger of fire and/or injury.