With a grain of salt.

"Don't take this personally..."

"Don't take offense, but..."

"Take this with a grain of salt..."

These phrases let the speaker off the hook. They aren't asking for permission. They are simply assuming it.

They know that what they are going to say is harsh, is going to make the listener feel worse. But the onus is on the listener to not feel bad.

Maybe, it might be helpful to see how we would feel if we were receiving what we are about to say.

If the food is inedible, it doesn't matter how much salt we add to it.