Yeah it seems drastic, but it really isn't. You can add someone in two seconds, let them calm down for a day or two, and the next time you come across a post that is hidden because you've ignored the member, you have the option right there to remove them from your ignore list. You could ignore someone for 1 minute, or forever.
But, I can see your point. If you want to ignore them, just don't read their posts, you don't actually have to physically hide their posts. Also if something they posted is totally inappropriate or against the site rules (or classified rules), report the post.
In theory, we really shouldn't have to have an ignore feature at all, but if you want to use it just because someone is getting on your nerves, the tool is there so you can ignore them for a couple of days or whatever you want.
Obviously, I will never ignore anyone.