So, now we are the bad guys of not just bending over the first chance we get? Cry me a river.
We gave Dembele pretty much the best stage he can develop on top level last season. An offensive minded European top 10 team, which played a good role in the CL and won a national trophy. He was allowed pretty much a free role with players around him dedicated to make him shine. He also had pretty much a starting guarantuee despite suffering through two minor slumps in the season (something that would not be allowed that easily in elite clubs).
Now we want him to stick around for longer than a fifth of his original contract. He wants to go to Barca, Barca wants him. We want compensation. Given the circumstances (key role, long running contract, late in the window) that compensation grows to a massive figure, but not an impossible one.
Blocking his transfer would be us demanding something Barcelona can not deliver, but they can. Everybody knows that. They just choose not to do so.
If you want to a have a guilty party why this transfer might not happen, Dortmund is the wrong direction you are pointing at. You have to point further South.
I'm referring to Dembele in that post. Not Dortmund.