Linux

In one instance I discovered McAfee to disable write access to /etc/{passwd,shadow,group} effectively disabling a user to change their password. While SELinux will properly handle that by limiting processes, instead of creating a process that would make sure those files aren’t modified by anyone.

That sounds like McAfee alright. Most antivirus software doesn't do stupid shit like that, though. Linux has plenty of APIs and call filters to detect and prevent attacks on passwd. In its default configuration, ClamAV and various other antivirus tools don't even do anything but update their definitions until you explicitly call them to scan a file.

People need to understand Linux comes pre-equipped with all the necessary tools and bolts to protect their systems. They just don’t all live in the same GUI, because of the real complexity involved with malware…

That's the thing, every operating system has that. Microsoft has everything from signed drivers to exploit guard and even Microsoft Edge running entirely inside a virtual machine to combat any form of browser exploitation. Even everything from Microsoft's EMET has been included in Windows. ACG/EAF/IAF/various ROP detection mechanisms/DEP/SEHOP/StackPivot/CIG/integrity validation, you can all enable it to prevent most exploitations in almost any program on Windows. Linux doesn't come close!

I can count on one hand the amount of people who actually bothered to run npm install in a container, let alone something more secure than that. I've never seen anyone validate the checksum of any downloaded executables or packages, let alone upload them to virustotal or any other virus scanner.

The current security mindset of Linux users seems to be the same as that of macOS users ten years ago; "there are so few viruses for our platform that we don't need to be careful". Apple prevented that from becoming catastrophic by making macOS a Big Brother operating system where it's practically impossible to install a driver, where every single executable is checked with Apple's servers. Still, macOS malware is a real thing, and so is Linux malware.

With Steam Deck bringing Linux to the mainstream (as well as provide guaranteed access to a device with games and transferable collectables connected to a valid account) I expect Linux malware to start becoming more than developer/server oriented. Linux has some nice tricks (unlike Windows, it doesn't set the execute bit and add an optional flag on new files by default) but it's vulnerable to others. curl2bash is the norm for various professional programs. Discord tells you to open .deb files from their website, normalising the "persist this file on your system, trust me". In fact, the standard EmuDeck installation method is "download this .desktop file to your desktop and double click it", like you would with any Windows program.

I don't run an antivirus program because I consider myself smart enough not to get infected (dangerous, I know). That doesn't mean new users shouldn't be running antivirus, though. Just because you don't need antivirus, doesn't mean that someone with no experience with SELinux, AppArmor, containerisation or execute bits shouldn't. You just have to avoid the shittier companies (the free ones, the paranoid enterprise ones).