Second cup of coffee hit the brain.
The main objection to systemd lies in the the word "monolithic" in the linked article. Monolithic software tends to be big, tries to do everything, Swiss Army Knife instead of a scalpel.
Why is that objectionable?
Complexity. Hard to test everything to prove there are no bugs. If there is a problem, hard to find root cause (trust me you want to fix root cause instead of patching symptoms. Think of : do I keep repairing shingles on my roof or reroof the whole house).
Go back to one of the original design elements of Unix. "Do one thing, do it well, do it correctly, be able to use stdin and stdout".
Do one thing means software is smaller and easier to prove correct. Stdin and Stdout let you link programs together.
Lets say you're logged in as username tim. How would you get a count of all the processes running under username tim?
You could have some program that takes all kinds of arguments that you have to look up every time or you could just do:
ps -ef | grep -i tim | wc -l
Small programs, doing one thing well, linked together via stdin and stdout.
People often say that Unix isn't very user friendly. The reality is that Unix (Linux) is very user friendly, it's just picky about who it's friends are.