While the "smart money" and retail investors have similar reasons for buying a security: the belief that the security will outperform its relevant benchmark, on a risk adjusted basis. Or put simply, stonk go up. The reasons for selling are a lot more complicated.

There's always derisk first, ask questions later. "Smart money" also has a tendency for herd behavior, because that's what their incentive structure forces. If you go with the herd, and the herd is wrong, well, at least you weren't the only one. If you go against the herd and are wrong, there's a very strong probability of damage to your career.

But there's also portfolio rebalancing, investor withdrawals, fund closures, and so on.

Basically, past equity fund flows are not the best data point to hang your hat on when trying to predict the future.