In some cases that might be true, and as such, there's a gray area, for sure. But for every insane Brittany Spears, there are many, many more people who have a right to carry on cretain aspects of their lives with a reasonable amount of normalcy.
I'm sympathetic to celebs being accosted during intimate times of their lives, but they're the subject of the papparzi because of skillfull manipulation of the press while on their way to stardom. "Take a pic of me with all the other coolest people." "Take a pic of me and my hot girl getting out of my cool car, and make sure you ask about the cool labels I'm wearing, so I can get more free cool stuff. " "Take a pic of me with Denzel, so producers and A-list actors may think I'm cool, and offer me work."
Celebs know the downside of fame is the vultures snapping pics at every turn. I just didn't think the guy deserved the smack-down by merely follow them on a public street, is all. Sneaking into a wedding? Yeah.