IMO having a security bug in systemd is not acceptable. Commits should be carefully reviewed. That other projects (even if these include very important ones) have way more is "meh".

From what I understood from the systemd code is that it's written pretty defensively. I quite like systemd because its useful, thought out, etc. But then I want all that without any drawbacks (because why not!). Probably unrealistic, but nice to strive for a perfect project.