It's not about can't let go, it's about don't want to let go

Many minds think, believe, and say that they can't let go or don't know how to let go.

It's actually they don't want or reluctant to let go. That's all.

"I am hurt and suffering. I don't deserve this. I want them/him/her/someone else to be hurt and suffer as well. They/He/She/Someone else deserve(s) this."

Similarly, in all kinds of unpleasant, undesirable, or disagreeable experiences/conditions/affairs/interactions.

If (it) is something unpleasant, undesirable, and disagreeable, if (it) is something hurting, if (it) is something burning hot, just let (it) go.

Can't really blame anyone or anything, if the mind doesn't want or reluctant to let go.

Be free.