Anyone with experience doing presentations knowns that the only safe choice is light background, dark text.
It is the most readable in most environments.
If you go for a dark theme, you will soon discover painfully that projectors are terrible at projecting darkness, and it gets very difficult to read in light environments.
Many offices and meeting rooms have windows. Sometimes it even gets sunny outside. When there is ambient light, that light will take over the dark theme and the presentation will become light-light over light text. It may be hard or impossible to read at this point.
Before you make a presentation. You should go the presentation room and do a dry test. Get to the other side of the room, see how the colors are rendering and whether the font is big enough.
Of course, all of this is especially true for important presentations which took days to prepare, even more so when it's given in another location you don't know the details about. Short informal presentations are unlikely to get you fired if they bomb (note: not caring about the presentation because it can't get anyone fired is not exactly a good way of thinking ^^).
For the experience, someday you should try being a presentation jury at a university (or similar). You'll see students coming with all kind of themes, sometimes dark. You'll get to see many times what it's like to have a dark theme... and have to change it at the last minute because it cannot be red in that room.
Conclusion: ALWAYS pick a light theme for presentations.
Special Case: Dark theme are reserved for dark rooms with no windows and lights turned off.