I just realized (I didn't fully read the reference) but my reference does not accurately describe the ecchi genre.
Ecchi is dirty humor, thus it has comedic purpose.
here's Animenfo's deffinition:
Ecchi anime contains very light sexual themes, such as sexual comedy, transvestites, lecherous grandparents, the occasional bare breast, but never any actual sex. Lots of nosebleeds and potty humor.