Yes, the reasons are not very impressive ones, but nonetheless.

I don't see the relevance. Linux is no good target, because there are not many linux boxes compared to windows/mac and because 100 linux boxes might require 10 different ways to attack them, while 100 windows boxes might require 1 or 2. There is nothing obscure here, just diversity.

Diversity is always a good tacit in defeating pest. Learn from nature / biology. Monocultures are unstable and have to be superficially stabilized with great effort.

similarly the guy says, he creates variations of the code in order to avoid detection. a world where hunter and the hunt all diversify.

Surely Linux would be a good target? There are hundreds of thousands of Linux servers out there and they will have a lot of bandwidth / CPU etc.

But how do you get the malware on the servers? Most malware spread by tricking unsophisticated users into install them. It is much harder to trick a system administrator to so. Exploiting a vulnerable public facing service is the alternative. However, that option is out of reach to all but the most dedicated attackers, assuming you keep the system updated.