Because correlation is not causation. If A and B correlate there's 3 options:

1) A causes B

2) B causes A

3) C causes both B and A (in some order)

4) your correlation figure is bullshit (hence not counted in the 3 options, but certainly with news these days, it must be mentioned)

A famous way to illustrate where this goes wrong is to show a map which libraries that loaned out Harry Potter books, and a map of where poodles got raped. Very high correlation, and obviously an example of the 3rd option.

(obviously both were caused by population density, which leads to both library creation and poodle-related crimes. And probably non-poodle-related crimes)