[Bacardi]

In SourceMod plugins, like basecommands, if you set invalid map file (by default, it is already), plugin list all maps automatically from maps folder.

When you want use map file instead, you need make changes in ...addons/sourcemod/configs/maplists.cfg

*edit
Because we are talking about CSGO, you need keep in mind, there are two kind map cycle system.
- CSGO game own map cycle by gamemodes.txt
- SourceMod map cycle by hidden cvar mapcyclefile, mapcycle.txt is default.