Even Linux and macOS are target of hackers but the number of people that use linux are mostly those that know more about the technology and IT
Could we claim Android users as Linux users too?
If we consider Linux as Linux kernel (just because there is no canonical Linux operating system, Windows style), I think Android users could well count toward being Linux users too. But in no case can we think of them then as more literate technology wise since they are basically the same users who are using Windows on their personal computers and notebooks. I don't like Android much, but I have heard only about a couple of viruses there, and needless to say, they didn't raise as much noise as many Windows viruses customarily do. In fact, they didn't even manage to spread in any significant degree
Well I didn't mention android but I don't think that android users (mostly mobile and tables) should not be counted that are using Linux.
But in this case it means that they are target of hackers more than other platforms like ios and windows phone as it's easier to get infected even if the app is in the google play store.
But ransomware as far as I know infects only PCs and servers not the mobile phones and tablets
You won't find a lot of ransomware on Linux desktops or servers
And I won't be surprised if you won't find any at all. But this is irrelevant since this is not what your point was about. Basically, you claimed that Linux is only (well, mostly) used by geeks (and that's why there is no ransomware for it) which is obviously not the case. It is used by essentially the same folks which use Windows (or MacOs, for the record). But somehow we still don't see packs of viruses for Android, even though the number of Android users by far exceeds the number of Windows users. How come?
Linux is a system where viruses doesn't exist or viruses can't easily get in because it was programmed to be invulnerable to viruses and other harmful stuffs in your computer. And this ransomware is out of the topic here since it can't penetrate the system, and what you have said is indeed true. Maybe he thought that the population of the android users is larger than the population of windows users.