Because you can not download software, which you want. You must search in depositaries - where you can not find what you want or choose outdated software in bundle download. Even good antivirus soft is not so easy to find - mainly outdated. Linux is probably the worst OS software in the world !!!
Why such hate? Stupidity or just trolling? All of your pseudo arguments are completely false of course.
a) "you must search in depositories" - there is no such thing - it's called repository, and you don't have to search here - you can download and 'install' whatever you want
b) "choose outdated software" - well what could I say
completely false - in fact you can get always get the newest soft available(made so far)
c) "good antivirus soft is not easy to find" - false again... is as easy as looking into repository
(or searching on internet see a) ) newest version always available(see b) ); And it's good to say that estimately about 90% of viruses targets Windows/Mac OS/Android(this is based on Linux kernel, but security is poorly made there) so just by installing Linux distribution you got the very efficient antivirus
d) "worst OS in the world" - it's like on of the most important software in the world
most of the web you visit is running on Linux based servers (not even mentioning non-pc devices, etc.)
In the next few years gaming will turn into Linux distribution(see Steam and it's intentions) and Windows will have a hard time to survive(unless they will justify they infinetly higher price than Linux distributions for personal usage).
So just plz
kill educate yourself and don't spit hate on things you have no idea about.
P.S.: no offense meant in this post