Read it and here's what I think: It's a subtle difference. By overriding the trauma associated with the memory, it becomes possible to forget it, but it does not in and of itself cause you to forget the memory.

When the memory loses its potency, it becomes just another passing detail. It doesn't have any power over you, it will not haunt you, and in time can be forgotten.

Except the drug does not "override trauma". It actually causes you to forget the memory you are recalling.

Judging by your username, I'm going to guess you are familiar with the operation of DRAM: it must periodically be refreshed by reading the data out and then writing it back in. Human memory works the same way (albeit without the requirement of continual refresh). The drug in the article interrupts the write-back process, and the memory is then lost.