As an active LDS member, I want to pull out a few things I noticed:
1. I have been called antichrist many times in life by many well meaning generally kind people, that is nothing overly telling. Truly a case of MH with this one. But obviously MH in an echo-chamber of negativity as with nearly all other mass murderers.
2. The assumption that priesthood blessings were frequent or coerced is extremely highly speculative. We baptized a woman with a child suffering from a rare disease a year ago and I don't think a single blessing has been given. It is possible, with 'bishop roulette' as was phrased by Megan, that an overly zealous membership would have encouraged it, but that level of zealousness is rare in my experience. (P.S. I love that phrase though)
3. It was posted that tattoos would be removed for his ceremonies. As Megan said, that is probably only the case if they were obscene and visible, and that is still somewhat unlikely. This does indicate that he was at least a baptized member though probably, but obviously has rejected the tenets more recently. We took a woman through the temple last week who was covered in tattoos from before baptism so I don't think this would indicate a valid sticking point in his bias. Again, there is a spectrum of Karen's everywhere, but it is unlikely that anybody was restricting him for having any level of tattooing on him.
4. Since congregations are geographically defined and coerced, I looked up his address and he would not have been a member of the congregation in that building, and it is not the closest building to his house. The congregation inside was the only group that used that building, and based on the size of the building it would have probably had 200-300 people in attendance at that time. We did not see heightened numbers yesterday as a result of President Nelson's passing, so that is probably not a factor.