Should I sell shares when they're at a loss? | Market uncertainty & market volatility

[@splinter1012]

I am confused about the rebalancing. If you sell ETFs that are doing well and put more into EYFs they are doing poorly, isn't that the opposite of cutting your losers and holding onto your winners? Take profits on the winners to ritate into other investments sure but I don't follow the rationale of putting more into your losing ETFs Could you clarify?