It is just you who did not know details about blockchains.

If you are into a chain which use a hash-function that is the same as a much larger chain, it can be overtaken at any minute.

It is no news, and you are at fault here by mudding the waters.
No one has hacked a leading hash-function chain.
No one has ever claimed that a non-leading hash-function chain is safe.

You can't mix the two and pretend it is the same.