That's the thing that I don't get. Dortmund actually poaches players from their rivals almost every single summer, they use their financial strength mainly within germany while Bayern mainly purchase abroad with a few key signings within Bundesliga but it's Bayern that has the reputation of doing what Dortmund actual does.
Exactly, thank you.
In recent years Dortmund bought way more players from direct competitors than Bayern. Yet, as you say, the pulic consensus is different. It's a narrative that has some truth to it (thinking of Ballack, Zé Roberto and Lucio we got from Leverkusen or Karlsruhe if we want to look further into the past) but that was heavily inflated by the inferiority complex by Dortmunds staff and fans from 2010 to ~2015.
Every week Klopp, Zorc and Watzke cried in interviews about the financial advantage that Bayern has. Klopp even accused us of stealing his superior, never before seen tactics. And of course having more money than him and stealing his tactics is the only way to beat them. At least that was, what they claimed again and again: "Bayern only wins because they have more money and can buy players off of their direct competitors."
You can see how successful they were in transporting this message, because it's not only common in germany across fans of all clubs, but as we can read here on Redcafe or Twitter the international opinion seems to be the same.
At least in germany the tides may turn slowly. Fans of many clubs called out Dortmund's hypocrisy after buying Rose.