Of course you can, and there are plenty of ways to do so that don't break the site guidelines. Cheap, snarky one-liners are not the way. If someone's posting about their own work, there's no need to be disrespectful.
It's also not helpful to post such a clichéd dismissal of what someone else says or their work. That's in the site guidelines too.
We have no problem sharing our codebase with customers, especially if there are concerns like this. Shoot me a msg if you are genuinely interested in anything you have read.
https://info.varnish-software.com/blog/introducing-varnish-t...