nginx is a fully fledged webserver with logging enabled out of the box, and other bells and whistles. By just having logs enabled for example you're adding significant load on the server because of log formatting, writes to disk, etc.
At the very least include the configs of each server tested.
I haven't had the time to add configurations for every server tested (esp. Apache & NGINX) but the main point here is to showcase the Node.js vs. Node.js with µWS perf. difference.
If not, then you should have taken the time to provide the information for a fair comparison with the other stacks.
As it is, you're just asking the community to take your word for it.
I think it's completely understandable that he threw in the others, probably default config, without caring much about it since they weren't the point of the writeup.