I've never tried making it, for exactly the reasons you mention. One point many recipes make is to remove all of the stems, then crush & heat the juice. Any wax that forms when it cools should be removed. But, you still end up with an astringent product, just not as bad. You'll probably have to use campden and sweeten the final results.
Herbalists use elderberry for wound cleaning. The pucker power is a good thing then!
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk