Your club does not have a similar youth setup so there's no point in pretending to understand the difference. Simply put, he's played for Barcelona from childhood and for longer than his current club. Moreover, he was poached. He like any other cantera player is free to make career choices they feel suit their interests best. Feigning ignorance that somehow Arsenal formed this player from 15 (Like Cesc) is laughable - there's a reason why Arsenal keep dipping into the club's cantera, it's cheap and they can profit later from a big sale when the player's quality is not in question.
Not like any other.
And yes, of course, when you pursue a contracted player the process is more or less the same for any player at any club. Where's the moaning? The MD article is more likely a public stance to motivate the player to push for the move or understand the club will not pursue indefinitely or pay over the barrel for one of their own
Pogba? First, the player himself was poached from France by United. Second, Pogba was not developed or formed at United when he arrived at 18 else he wouldn't have been pursued/poached in the first place. Third, Paul saw out his Professional contract at United (Which Bellerin did not have at Barcelona) before leaving for Juventus due to not being given playing time. None of these remotely apply to Hector Bellerin or any other poached cantera player. That example is so poor on so many levels and no, the concept is not the same - had he been played or given some senior call ups United wouldn't have had to pay an enormous fee to bring him back.