Sunni is a massive section of Muslims all with different beliefs though. It's like the difference between the Western churches and Eastern Orthadox churches. There's still a massive variety within each part.
I'm willing to bet that if you look into the backgrounds of these self-appointed community leaders and protesters, you'll discover that they almost all attend a Salafi or Wahhabi mosque, which are Sunni, but a fundamentalist variety. Unfortunately, given the amount of funding that Saudi Arabia puts into spreading this toxic variety, the ideas are seeping into Islam more widely. But in principle, these people are like the Orthadox Jews who protest when a lingerie advert appears in their street, or the evangelical Christians that protest when someone puts on a play taking the piss out of Jesus, who might belong to a wider group of Christians, but are still a small extreme sect within that. However, those groups tend to stick to protests, whereas the Islamic variety tends to be protest backed up with the threat of murder.