Yes they do, the cracking scene ethos is all about technical one-upmanship and the thrill and glory of beating copy protection. Or at least it used to be. The really smart ones do it for their own enjoyment or ideological reasons.

Not really, back in the MS-DOS, Atari, Amiga, Acorn, Mac OS days you surely need to first scan every single floppy before putting on the computer.

The cracking scene was equally full of virus.

Only in the very early days, during the genesis of the demoscene, it was as you describe.

As I recall the early virus guys were more like vandals who wanted to cause problems for the thrill of it than guys operating international rackets like they are now. When was the last time you heard of a virus that just formatted your hard drive or whatever?

Nowadays they encrypt it instead.

Yeah, and then they ask for a ransom. Not really the same as destroying stuff just for the thrill.

There are lots of attack vectors, not just pirated software, and viable ones depending on desired outcome can range from email, browser, and direct software spread (pirate games). MacOS isn't safe, and neither is Linux though the attack vectors will vary.

If all you want is a DDoS, a fake advertising account can often deliver the desired effect without actually infecting anyone. It really depends on what the cost/benefit vs desired outcome is. Not everything requires root, and very few people actually check checksums for things they download.

Quite true, specially in the days of "curl | sh" fashion.

Don't they? Pirates have been around since long before viruses really became a problem. What was their motivation then?

Virus were already a problem on MS-DOS, Atari, Amiga, Acorn, Mac OS.

Probably only during the 8 bit computers it wasn't a problem.

How does piracy come into this?

lots of binaries are not only patched to circument DRM, but also to contain malware

How does this relate to the issue that antivirus companies do horrible things and hold ignorant paying users who don't even know how to pirate software, and legitimate software producers hostage like some sort of technical mafia?

Because they only became a business due to the people that were pirating software in the 80's.

Thanks to the increase of virus across MS-DOS, Atari, Acorn, Amiga and Mac operating systems, specially on boot sector floppies, the general public learned that anti-virus were required software to always have installed.

So are you saying that if people didn't pirate stuff the viruses would not have spread? Presumably because they would not be using floppies as much?

Yes, it was the spread of pirated software, which crackers usually filled with virus "just for fun", alongside the lack of protection mechanism in the desktop OSes that gave rise to virus.

Thus making anti-virus a software package, that most home users would buy, in my home country even that was usually pirated.