Anyone can ssh into a server and apt-get haproxy and tweak the configuration and get it "working" where the definition of working is accepting and routing traffic. But that's just a hobby setup. When people say setting up a load balancer is complex they are talking about professional setups, not a one off software install on a single server.
But I want to be able to update my haproxy config with a git push, and roll it back with a single command, without sshing into anything, if something goes wrong. I want my everyday administration to be simple. Not the initial setup.
Now set it up in 30 data centers around the world, with the ability for dozens of different teams to add and change their applications, and across multiple staging and QA environments.
My what and what? :P I do get your point, it is "easy" for some definition of such, but to be fair, k8s would automatically put the ip and port in for my part of it all at least.