Because it murks things up. Same as network-manager pointing /etc/resolv.conf to 127.0.01, and then run it's own resolving dnsmasq on that address. It's trying to be too smart in resolving a problem. And now, when I cannot resolve a hostname, can't even edit /etc/resolv.conf, or trust it's contents. I now have to look into /etc/dnsmasq.conf, interpret it, find out where it stores the real resolv.conf file and have a look in that file.

It's overcomplicating things.

Yes, I love automation. I puppetize and ansible-ize the hell out of my serverparks. But udev, kudzu, network-manager and now systemd: they're solving the problem by creating more complex problems.

I just have very bad experiences with automagic systems trying to outsmart me. And failing miserably, costing me a saturday-evening with the missus. And outsmarting me ain't even that hard!