Open but unknown Sperm Donor. Ethical?

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So my partner of 5 years and I originally planned to have a friend donate his sperm. We knew for years we would ask him and when the time came he actually offered himself... and then stone cold flaked. For some time I felt like our idealized dream had been shattered but I've come to realize this wasn't a life our ex donor truly wanted and that is ok. Well after our first fertility appointment, we found our doc was steering us toward sperm banks in general. The sperm has already been tested, tried and true! No legal B.S.! And although the donors are all anonymous now, some are "open" to contact when the child turns 18. Best of everything? So I signed up for California cryobank and I do have to admit it has been a bit addictive. We have settled on an open donor who has a lot of the personality traits and characteristics we like in a person, not to mention adorable baby pics. We bought a vial for just under 1k for out first TTC next week. I'm over the freaking moon excited. But there is a part of me that wonders if I am doing the right thing? There are quite a few donor conceived young adults on YouTube who express a sense of sadness regarding the unknown. Some are angry. There is even a trailer for a documentary against any sperm/egg donation that seems to be produced by donor conceived people. Has anyone talked to a donor conceived person with an open donor? Anyone else concerned?