It's Jagex's fault for making a game where the only thing you do is click for hours to gain one measly level.
I mean, what the forget is the point of wasting all that time? In other games, gaining levels is fun, and you don't even realize that you've done work. In Oblivion, I enjoy a challenging fight against a group of bandits or a forest wyvern and then see I've gained some level. In Runescape, you must spend so long just to get 99 in some skill. And what is the point of getting level 97 or 98 if they have no special perks? Filler, that's what it is. stuff to make you spend more time glued to the stupid game.
If you ask me (caution the following sentence is ANTI-HARDCORE) they should make it so that you only have to level until 50 and then 99 comes right after. It makes no sense, I understand. But then leveling would go pretty fast, and you'd only have to grind for that one last level.
So yeah, it's their fault that people decide to bot.