I think it’s more about control than sending what you love away.
“Set it free” means let your love interest choose to stay or leave on their own, don’t try to keep them caged.
Depending on what you mean, it’s possible that your love you regret letting go of wouldn’t have lasted even if you had held it and fought.
Though if you mean you took that saying and thought it meant you needed to push your love away to see if they returned, then yeah, that’s not a great strategy.
Yeah, the latter is how it was explained to me. Like, literally break up with the person you love to see if they’ll fight for you to take them back. Or push them away and wait a few years to see if they magically reenter your life or something. Crazy, I think some people believe they live in a hallmark movie