I routinely firewall data centers. Why? Because too many of their customers are scumbags.
The bots. The scrapers. The exploits. The spammers. The inappropriate links. The data centers which harbor all the riff raff of the web. Get lost.
In an earlier time when I was naive they got by. Then one fateful day I saw my content published on somebody else's site and it was on.
Luckily my content has been published on my site long before it ended up on some illiterate no talent dirt bag's site later ...
So I switched to Apache and started installing and getting up close and personal with all manner of modules and associated scripting designed to control access and voila — I started excluding those problems which pervade the internet thinking they own me. AS IF ...
Should you suddenly encounter a 403 (forbidden error) when you cross my patio it's due to your (or your host network's) reputation preceding you, your user agent, your web site, your previous commentary, your query string, and/or any number of other kinds of disqualifying access which may have gone down in the past. To my dismay I've amassed quite the detailed catalog of methods, agents, and networks over the years. It speaks poorly of some of our fellow denizens of the internet.
Only now I'm much less likely to drop my shields as I have been in the past. The resilient young become the wise old. I'm not your commodity. I'm not your bitch.
I don't like exclusionary practices. There just came a time when I had enough of rogue networks supporting a deviant user base with too many exploits, bots, scrapers, spammers and the rest of the vermin infesting the internet.