It's the principle of getting what you pay for.
If you don't pay anything you shouldn't expect anything and be glad for what you get for free.
If you don't pay/contribute anything and start harassing the people that bring out the client/scripts for free then you are a leech, and even more pointless than the world itself.
Stop leeching then.
Leeching is more than just using something for free, it's using something for free and expecting extras you didn't pay for and therefore not deserve such as costumer service, frequent updates, etc..
It's a portmanteau of the words bot and entrepreneur, you can say it in whichever way you want as long as you make it sound as pretentious as possible.