I thought of something: in scifi wouldn’t time travel be considered inherently evil? Like let’s say you stop WWII from ever happening. Then baby boomers, the children of baby boomers would be killed/erased as a result.
Not to mention if such a civilization were able to travel back in time wouldn’t that cause pretty much a time war in which the different possible timelines have people traveling back in time to ensure their continued existence? Like let’s say you kill Hitler that would cause someone from say 10000AD to travel back in time to stop you so that everyone they have ever known don’t die, but as a result of them stopping you someone from 10000AD in the new timeline stops the person that stops you from killing Hitler so that their timeline can continue.