Do citations have to be put in context? When citing, does it have to be obvious from the sentence or placement of the citation what exactly is being cited or why the citation is there? Sometimes I feel like people cite things such that you can only figure out why there is a citation after reading the cited article. Is that ok or should the purpose of a citation be obvious from the text?

E.g. should


  In the field of bla {cite bunch of reviews} people do lots of cool stuff.


be instead replaced by something like


  In the field of bla people do lots of cool stuff. For recent reviews see {cite bunch of reviews}.
Every paragraph has a purpose. The answer to your question depends on the purpose of your paragraph.

Clarity in academic writing is always good, but you should weigh whether being explicit is clarifying or obscuring the important points. "For recent reviews see {cite bunch of reviews}," may be fine if you want to direct the reader's attention to the existence of those reviews. Perhaps you're doing a metareview, or for some other reason want to track development of the literature.

But the terser version is cleaner if the existence of reviews is tangential to your point. The reader can investigate further if she wishes--hopefully the titles of your cited works make their purpose clear, so she's not digging around to figure out what they're about!--but she can also breeze past the citations to your main point. Extreme concision in citations is widely accepted. I've seen citations to my work (broadly, in interdisciplinary social science) where I was not entirely sure why the authors thought it was relevant!

So what is your paragraph trying to accomplish?