One of the tenets of our legal system is that our laws are applied evenly so that people understand what is legal or not.

If the interpretation of a law changes with time then you could find yourself a foul of the law when previously you weren't. It's why "precedent" matters.

Absent precedent we need to understand what the law makers meant with the words they used. Especially for old laws since language changes over time.

This is an important step and how the system works. We cannot and should not skip it.