The "economy" of this game is not a true economy at all. The vast majority of stations are not profitable trade cogs; This is not because humans are over-trading; And many times it is not because NPC's are over-trading either (although the NPC over-trading is vastly more common than human over-trading in places where trade would be viable); At the end of the day, prices are driven by supply and demand. However, without actually understanding what the terms "supply" and "demand" actually mean... you end up with something that is not an economy at all. And as such, it is broken from the very beginning, before NPC's or humans get involved. It is for this very reason that Slopey's tool is NOT a bad thing. In a working economy, his tool would not be needed at all. The very existence of his tool indicates a broken economic model.
In reality, demand is defined as a consumer's willingness to pay for a good. This willingness is influenced by their own personal preferences, but more importantly it is also influenced by the price of the good. As prices go up, the consumer desires less, and will seek out substitutes or other options altogether. As prices go down, the consumer desires more. Similarly, supply is defined as a producer's willingness to produce a good. In this instance, the producer similarly faces a decision about how much to produce (or not produce at all) based upon the price of the good, as well as the COST to produce it. They would produce more if the price is high, and less if it is low. But ultimately, cost must always be factored into the decision. If the cost is higher than the price... they would stop producing and find something better to produce.
Because this game does not incorporate any of these types of decisions into determining "supply" and "demand," they are not supply and demand at all. They are simply 2 columns with numbers under them that are pre-determined by FD. And while those numbers may fluctuate depending on the amount of trade taking place, the real issue is that virtual producers and consumers do not make informed decisions. They simply add and subtract from the market on a daily basis regardless of the price. This is fundamentally flawed.
Ultimately, production and consumption decisions (which are absent from this game) work in reality due to the AVAILABILITY OF INFORMATION... informed decisions. This game is stuck wrestling with a notion that people should not know the prices at different stations without going there first. But in reality, interstellar trade would not exist without readily available information to connect producers and consumers. Truly fixing the broken economy (which is probably an impossible task given the complexity) would not occur by prohibiting 3rd party tools which enhance information gathering ability. Fixing the economy happens by incorporating the ability to gather information efficiently into the game itself.
Regardless of the EULA or any of the legal aspects... the notion that Slopey's tool (or any others) are breaking an otherwise working economy is entirely incorrect. The reality is that their tools are the best option we currently have in dealing with an economy which is completely broken from the beginning. They are the solution, not the problem.