A lot of charities dont want old computers because they're hard to sell, dont do much and in some cases can be a pain in the butt to dispose of. Less so now that many communities have electronics recycling programs for free.
Not that long ago Goodwill wouldnt take a television or computer monitor, they might still not want them.
I had a hell of a time trying to get rid of two monitors and two 1990's era computers some years ago. Ended up leaving them out in front of my wifes old house overnight and that took care of it.
Be fearful when others are greedy, and greedy when others are fearful. Just another form of "buy low, sell high" for those who have trouble with things. This rule is not universal. Do not buy a 1973 Pinto because everyone else is afraid of it.