I don't know if this is true, but it's irrelevant.
Sexual orientation: Buddhism's stance on sexual morality is pretty simple. No rape and no deception (cheating on a partner, sex with someone underage, and misleading a person to acquire sex all qualify as "deception"). There aren't rules about before vs. after marriage or gender. Buddhism is focused on practicality and harmony, not adherence to assertedly eternal rules.
Immunity to pain: not sure of that one. The brain is a powerful thing, and accomplished yogis (not to claim equivalence between yoga and Buddhism) can get power over their bodies in pretty unusual ways. However, Buddhism's main concern is the reduction of dukkha, which translates as "mental suffering". Focusing on the elimination of physical pain is not a primary goal. This wouldn't even be desirable.
Temper: I think you put your foot in your mouth here. Spend some time around some seriously accomplished meditators. Yes, there are difficult personalities and some strange (even arrogant) people. However, if you look at aggregate differences, the serious practitioners (and it has more to do with depth of practice than identification with "Buddhism" per se) are remarkably (on average; these are aggregate comparisons) calmer, less neurotic, and less self-absorbed than people without practice.
Something that complicates this discussion is that there are many varied forms of Buddhism, sometimes saying seemingly contradictory things. While it's important to be able to use the term "Buddhism" for the sake of conversation, we have to be careful of our scope in making claims.
To place this in perhaps more culturally familiar terms for Americans: the Hinayana (even this term is controversial) vs Mahayana branches are as different as Catholics and Protestants, with the Mahayana schools being basically as diverse as Protestantism.
Sexual orientation: Buddhism's stance on sexual morality is pretty simple. No rape and no deception (cheating on a partner, sex with someone underage, and misleading a person to acquire sex all qualify as "deception"). There aren't rules about before vs. after marriage or gender. Buddhism is focused on practicality and harmony, not adherence to assertedly eternal rules.
Immunity to pain: not sure of that one. The brain is a powerful thing, and accomplished yogis (not to claim equivalence between yoga and Buddhism) can get power over their bodies in pretty unusual ways. However, Buddhism's main concern is the reduction of dukkha, which translates as "mental suffering". Focusing on the elimination of physical pain is not a primary goal. This wouldn't even be desirable.
Temper: I think you put your foot in your mouth here. Spend some time around some seriously accomplished meditators. Yes, there are difficult personalities and some strange (even arrogant) people. However, if you look at aggregate differences, the serious practitioners (and it has more to do with depth of practice than identification with "Buddhism" per se) are remarkably (on average; these are aggregate comparisons) calmer, less neurotic, and less self-absorbed than people without practice.