What I'm saying is: Why do we continue practices that are destructive to the economy in the way you stated above?
You're putting your cart ahead of your horse. You need to first show that a practice is destructive. No one here has done that despite my continual requests for someone to explain how someone making more money makes someone else poorer. It's *not* a zero sum game, remember?
How can some knowingly support and apply this "trickle down" poison into our system?
First off, labeling it "poison" makes it hard to take your post seriously. Secondly, it's not about supporting and applying it. What you call "trickle down" (most likely anyway) isn't something we create and apply. It's the natural way economics works. We have to intervene to *not* use it.
Who are the ones responsible for dreaming up such an atrocity to begin with? Where exactly did it begin?
It began with the first guy realizing that if he produced more than he personally needed to consume, he could sell/barter/whatever that extra to someone else for the excess of whatever they produce. The result is that both of them realize gains from producing "more". The "trickle down" effect of this is natural. If everyone in society produces only exactly what they need to survive, then there's no margin of error. You get sick and can't gather coconuts today and you go hungry and die. But if you've gathered extra coconuts and traded them for extra goods (or currency later on), you can then use that savings to support yourself until you get better.
Some people then realized that if they had a lot of extra stuff saved up, they could lend that stuff to other people to help them start up their own productive enterprises. And thus "banking" was born. I could continue through history explaining how every little piece of the puzzle appeared over time, but I hope you get the point. No one sat down and thought about how to construct and economic system. It happened as a natural result of people in society doing what generated the best results.
What those who argue against these systems are doing is trying to have it both ways. They want the wealth generated by the existing system, but they want to take that wealth and use it for things which aren't productive. They believe that this is better for society as a whole, but have a hard time convincing people that it's worth it. Thus, those people have to convince people (like you) that the natural economic systems don't work and that wealth accumulation, rather than being the one thing that has historically helped people get out of poverty and become productive and happy, is really some evil thing which should be opposed. They demonize the extremely rich and play on most people's ignorance of how economic systems work to try to convince them to attack the very things that make their lives better every single day.
It is something that has bothered me for a long time. There has to be another reason other than the bullsh*t they feed to the public about how it creates jobs out of thin air.
Honestly, when I read stuff like this, I just have to shake my head. It's not about trying to do things, it's about what results from your actions. You honestly can't see that in the process of building a huge corporate empire, the head of said empire will end up creating jobs for a whole lot of people? And he'll have to create some set of products which are valuable enough to the people for them to want to buy? You zero in on the individual rich people, but don't look at what their money is doing. Overwhelmingly, businesses make money because they provide a good or service to the public which the public feels is worth exchanging their own money for. And along the way, they create the jobs which gives people the money they use to buy those things (that's the whole "trading the fruits of your labors" bit).
The owner of said company doesn't have to start out with altruistic motives. But the results of his actions will create opportunity and wealth for others along the way to making him wealthy. It's nearly impossible for a wealthy person to become wealthy without doing this. Certainly, economy wide, this factor is absolutely huge and contributes to massive benefits for the entire population.