Changing stocks holdings to bonds and/or cash holdings - tax implication?

Might be a novice question but I don’t see an obvious answer for this —

I see that a lot of people have sold over the past few months, either changing holdings to bonds or increasing cash piles so they can eventually “buy the dip”. I know that long term gains cause a taxable event, often times 20% (or less). For those who are selling their holdings for bonds, cash etc wouldn’t selling (even if high), paying taxes, and then re-entering the market when it’s lower be relatively offset by taxes? Maybe with the eventual rebound of the market, the taxes would be worth it, but it is hard for me to wrap my head around. Can someone explain?

thanks!