Uninstalled Sims 4, but files are still there.

Luc1aA1​  The Sims 4 folder in Documents > Electronic Arts contains user data: saves, saved households and builds, mods and custom content, etc.  It's not supposed to be deleted when you uninstall the game, or else there would be many many unhappy players who uninstalled and reinstalled to try to troubleshoot a game or system issue only to realize they'd also lost their saves.

If you don't care about preserving your saves or other content, you can manually trash this folder.