Thick freezy wavy hair

Why never thin it?   One reason, if you have longer hair, you don't want them doing that with a razor because it exposes too much of the hair's inside not cutting each hair straight across and makes it more damaged than necessary over time.  It could still be done with scissors though, and wouldn't be more damaging.  If yours is short, you don't care about that though.

Often super thick hair looks great with longer styles, as shorter ones tend to make it stick out more than down (I think it looks fine, but people who have it don't always like it).  Once the hair is near armpit length, the last few inches can be layered to make the hair thinner on the ends so it tapers instead of being thickly cut straight across at the bottom.

Without more detail, I don't really know what you have, what exactly you don't like about it, and what you want it to do.