Because it sucks less than dying of Rabies and boy you don't want to know how low the bar is here
I had a pretty low risk exposure to a bat this summer and decided to get it because it's so hard to be sure they didn't bite you. Wasn't a big deal, and I got quite a lot of the antibody injections in my finger...
I'm currently 1 of 3 injections into getting a rabies vaccine and it's basically like every other vaccine I've had. A simple, painless, injection in the arm.
I got it the same time as my first shot of the Hep B vaccine too.
In addition, it used to be the case that people received abdominal shots and the course was pretty intense. That has ended, but people remember it.
I believe in this discussion the context is specifically rabies.
> and why is it called vaccination not treatment?
It's both, really. You get a shot of rabies immunoglobulin (at the site of potential infection, i.e., bite) _and_ an extended course of vaccine at the same time.