Board Thread:Supergirl discussions/@comment-9346948-20170523001131/@comment-3423279-20170614180600

Correct, but people seem to forget that the wormhole that then became a time paradox and tried to swallow the city was connected to the Speed Force by virtue of it being a result of Speedster time travel.

All they have to do to make Eddie Thawne's actions have a reason is say he wasn't as okay with being forgotten as initially believed. To rectify this, he kills Iris West and destroys The Flash and is remembered until at least the 64th Century.