Oh, by all means, we agree about that.
Presuming to know what is in the hearts, or the nature of the motivation, of every couple who engage in intercourse who don't adhere to your rather truncated set of parameters must be really hurting your ears.
My parameters are hardly "truncated."
I believe that intercourse should be undertaken for spiritual, emotional and physical reasons and that it should be open to creating new life.
Others may wish to truncate the scope of sex to a level of mere physical - and physically barren - intercourse.
But I hardly see how insisting that sex has spiritual and emotional meaning and creative possibility in any way "truncates" it.