There is more to puritanical attitudes than sex. It generally means anti-pleasure.

One thing the real puritans are against that people have turned against very strongly is alcohol. It never stopped being a problem in the US, of course, but there are far more preachy teetotalers in the UK than there used to be, and government policy is very anti too.

Then there is the push for achievement and the acquisition of wealth. You are supposed to dedicate your life to the cause of high achievement, rather than stop to enjoy it.

Sex acts online actually fit in with all this as they are safe and controlled alternative to enjoying sex in real life.