You have to be careful about revealing certain information if, in so doing, you also reveal how that information was gathered. Revealing that info can compromise the source and cause it to dry up. Hypothetically, suppose we get certain intelligence data from an agent inside a facility. Revealing what we know about that facility might result in the agent getting caught. Not only would that cost us a valuable source, it would make others less likely to work with us.

As a real world example, there were news reports not too long ago about testimony in a terrorism trial. The testimony discussed how we monitored the terrorists as they used cell phones to communicate. Not long afterwards, the cell phones went silent. The source for some very important intelligence was compromised and it went away.

There are more types of intelligence gathering than most people realize. Knowing what is going on requires fusing the results from several types of intelligence. Compromising any of them weakens all of them.

From Joint Publication 1-02 Dictionary of Military and Related Terms:

intelligence — 1. The
product resulting from the collection, processing, integration, analysis, evaluation, and interpretation of available information concerning foreign countries or areas.

2. Information and knowledge about an adversary obtained through observation,
investigation, analysis, or understanding.

See also
acoustic intelligence;
all-source intelligence;
basic intelligence;
civil defense intelligence;
combat intelligence;
communications intelligence;
critical intelligence;
current intelligence;
departmental intelligence;
domestic intelligence;
electronic intelligence;
electro-optical intelligence;
foreign intelligence;
foreign instrumentation signals intelligence;
general military intelligence;
human resources intelligence;
imagery intelligence;
joint intelligence;
laser intelligence;
measurement and signature intelligence;
medical intelligence;
merchant intelligence;
military intelligence;
national intelligence;
nuclear intelligence;
open-source intelligence;
operational intelligence;
photographic intelligence;
political intelligence;
radar intelligence;
radiation intelligence;
scientific and technical intelligence;
security intelligence;
strategic intelligence;
tactical intelligence;
target intelligence;
technical intelligence;
technical operational intelligence;
terrain intelligence;
unintentional radiation intelligence.