My thought is if you’ve thrown it out with the trash, you have relinquished your claim to it. If there is anything in there you still don’t want others to have, don’t put it in there. As far as identity sensitive materials – buy a shredder, burn it, soak it in bleach, etc.- anything to keep someone from getting your information.
I don’t have to agree with the Freegan philosophy to appreciate the need to reduce the amount of items in the landfills. If someone else can use something I no longer want or need, they are more than welcome to it. In my mind, that’s a win-win for all concerned.