Q:

What is the meaning of 'don't read too much' here?

On this blog, both title and the first paragraph say: Don't/shouldn't read too much. 

China's Defence Ministry said today people shouldn't read too much into a state media broadcast of live-fire military and landing drills, just days after a landslide election win by an independence-leaning opposition party in Taiwan.

Now, to my mind, this phrase is not written in literal meaning here, and I could not find it in any dictionary. Is it an idiom? What is the meaning of this phrase in the given context? Is it written to tell people should not bother about it? It's confusing for me. 

A:

To read into something means to assume more than what is explicitly written or said.

read something into something
  to give your own meaning to something rather than what was intended Experts warned against reading too much into Friday's election results. People can read into his comments anything they want to, but no decision has been made.
  Usage notes: usually used with too much or anything, as in the examples

See the above and additional definitions at: The Free Dictionary

