"The criminal justice system does etc...." ("system of criminal justice" is unnatural, and "the criminal justice system" is a fixed and commonly understood phrase) In general, when speaking English, be very liberal with the use of indefinite articles. For speakers of languages that don't use articles, this is very counterintuitive, but it is the case in English that nouns are accompanied by an article more often than not. The nuances of when to use an article, and whether to use "the" or "an," are very subtle and require practice and exposure to native speakers. You could even reread this paragraph and focus on where I put a "the, this" and where I put an "a". It would be incorrect for me to write "be liberal with use of articles," or "for the speakers of languages that don't use the articles". Just paying attention to these things in native texts will be helpful

copy-paste from wikipedia: " the definite article is not used: with generic nouns (plural or uncountable): cars have accelerators, happiness is contagious, referring to cars in general and happiness in general (compare the happiness I felt yesterday, specifying particular happiness);"

In this case, yes, I believe you do use "the" because you are talking about a specific system of criminal justice. If you are not talking about a specific one, but you are talking about criminal justice systems in general, you might want to consider using "Criminal Justice systems" as you are talking about more than once.

Don't be fooled by the language used in captions under pictures, newspaper headlines, signs, lists of bullet points. We follow grammar rules carefully when we are writing essays, paragraphs, and sentences. There are many situations where, to be short, we use "telegraphic English" and leave out articles and use sentence fragments. However, just because you see a picture with the caption "English judge in robe with wig" or "Branches of govt: 1) Executive 2) Legislative 3) Judicial" does not mean they are correct English.