You can be indifferent to market swings if you know your stocks well. Or you can put your portfolio into neutral or bias for the upside if you're bullish or a little for the downside if you're bearish. One way to do that is to have a mix of stocks that have certain betas in your portfolio. When investors are bullish on the market, they like to have high beta stocks in their portfolios because if they're right, then their stocks go up faster than the market in general, and their performance is better than the market.
If investors are bearish on the market, then they use the low beta or negative beta stocks because their portfolios will go down less than the market and their performance will be better than the general market. And if they want to be neutral, they can then make sure that they have stocks with a beta of 1 or develop a portfolio that has stocks with betas greater than 1 and less than 1 so that they have the whole portfolio with an average beta of 1.