UV-A, -B, and -C are bad in different ways. Sunburns skew towards UV-A, while cancer and aging tends to be from UV-B and -C. Vitamin D synthesis results from UV-B exposure.
Sure, but as discussed elsewhere in this thread, the studies (at present, which doesn’t mean we won’t learn more in the future) do not support the assertion that sunblock prevents Vitamin D synthesis in any meaningful way, despite what a random blog post might tell you.
Amen. :) You're preaching to the choir. Health and wellness blogs generally service the theater of the placebo and hivemind ignorance bordering on mysticism.