Why is it bad to use your tablet to take photos or video?

According to everyone and their dog, it's "shameful" to use your tablet as your moment-capturing tool. Why is that? I mean, I could understand if you were at a concert and someone whips out their Nexus 10 and goes right at it, blocking your view. That would become annoying, but for other times, it seems like many people don't like it.

Keep in mind; it's not your device! I say let that consumer use their device as they wish. Yes, I realize that the [rear-side] camera of any given tablet may not be as good as today's smartphone's, but I really don't see reason to make a big deal out of it. I have used my Nexus 7 plenty of times at the beach to take videos and Photo Spheres.

"Tablets are too big, you look goofy when trying to get a picture." Why is that even the primary concern? The first cameras were five to ten times larger than modern day's tablets. I'm not meaning to come off angry with anyone, I'm just genuinely curious to why we are pointing our fingers at tablet-camera-users. If the application is available, then that consumer has the right to use it.