I'm thinking...no way poisonous. Herbalists (and cooks) have been using whole hawthorn berries (without removing the tiny seeds) for centuries without concern or symptoms. The major sellers couldn't possibly sell a deadly herb/berry without MAJOR disclaimers (and explicitly detailed instructions for de-seeding). And where are all the reports from the tens of thousands of lay-people in the last few years that have made tinctures & teas (and eaten the berries after making the tea, as Dr. Schulze described doing)...that ended up in the ER or in the grave? And the PTB would have already created a major explosion in the mainstream media (after shutting down every vendor on the planet).
Do I have "scientific evidence" that they're safe? Nope. Am I going to try to find any? Nope. Do I think you messed up? Nope.