I tend to lump surf kayaks and SUPs together and do not have an inherent problem with either wave riding vehicle. It is the taking of the concept and putting it into practice by the masses that tends to give me heartburn, especially for SUP riders because for too many it is an extension of a longboarding philosophy, "I can paddle easier, catch more waves and catch those waves before others, and therefore it is my wave." Ditto for many of the tow-in wave riding folks (I am not referring to towing-in on waves that are beyond a any normal capability of paddling to catch and ride, but those utter monsters like very large Jaws). The same goes for kite boarders and wind surfers invading the line-ups of surf breaks.
SUP'ing around on a flat day... help yourself. SUP'ing around IRI Northside (or Southside at Dumps!)... help yourself. Shoot the OC Pier... help yourself. Most other spots... stay away! I don't care to get hurt by an out of control monster vehicle.