Freezing meat does kill some bacteria and parasites on the meat.
However not all parasites will be killed by just freezing it.
What does really kill the parasites and bacteria on the meat is getting the meat to a hot enough temperature such as 165 F or above.
When you cook the meat to a hot enough temperature and cook the meat all the way through then the bacteria and parasites will be killed off.
That's why you want to make sure that your meat is fully cooked before eating it.
If the meat is not fully cooked then you can get worms and parasites from it and possible other bacteria poisoning.
Freezing the meat also helps keep bacteria from growing on the meat as well and that's why the meat lasts longer in the freezer than it does in the refrigerator.
In the refrigerator most meat lasts between 3 to 5 days but when frozen meat can last for up to a year and sometimes longer.