It looks to me that this is a topic in the "feeling good education" which, I believe is not education at all (more like sale of diplomas for big money and nothing to show for it), so I should not be commenting. But I do anyway.
First, many instructors/departments/universities do not permit phones or other electronic devices in the classroom. A student who comes to class to tap on his electronic device is not only disrespectful (why not wide open a newspaper and read it in front of your prof) but is rather disinterested in the subject as well. Second, students need to learn how to take notes, since that way they stay engaged, they learn to discriminate the important from less important and so on. Just because you can snap a photo, does not mean it is useful to you. Third, they are copying copyrighted material and that is a no-no, for mass consumption, such as youtube or like postings they end up at. Lastly classroom is not generally considered to be a public space, even at public universities (just consult numerous court cases) and therefore you do not have a freehand in taking photos of people without their permission. Finally, this is mostly caused by indecisive instructor. You are there to set the tone and establish the rules, not to worry about "hurt feelings" but to make sure you have classroom atmosphere conducive to learning and teaching effectively.