If people are not deliberately avoiding orgasms, as people on this site tend to do, then why would they be having less orgasms? Firstly, these people probably had poorer health overall. Sex is a physical activity and people in poorer health would be less likely to be able to engage in it. Secondly, a lack of a partner can have negative effects on emotional and physical health. Being alone has been proven to be bad for mental and physical health. So yeah, I can see why people who have less orgasms tend to die sooner.
No, it's not related. The average person gives up on living (orgasms included) and anything that might prolong a stout and healthy life, thus their health fails and with it their ability to keep the ticker going. A study like this is "lifestyle biased"
Sex and orgasms are not the same things. Lack of intimacy leads to depression and lonliness, and both of these lead to shorter lives.
Exactly. Proof of correlation is not proof of causation. This study is just asking to make a post hoc ergo propter hoc error.