The Jedi, here, are telling him that he needs to prioritize his training over his attachments. And Lucas agrees with them.

As I said, that’s not the same thing. That’s not Obi-Wan and Yoda saying “You need to give up your attachments to the people in your life.” They’re just telling him he needs to focus on his training and avoid throwing himself recklessly and impulsively into situations due to those attachments. It’s a lesson about patience and forethought, not about non-attachment. That lines up with what George is saying in those quotes.

Contrast this with Luke and Ahsoka in BoBF, where there’s this implication that they want Din and Grogu to never see each other again for Grogu to become a Jedi.

Lucas never liked Mara Jade. Ever.

He didn’t veto her, though. He vetoed many other proposed EU ideas, but not that.

Edit: It’s also telling that, even in George’s own words, he says that Luke is acting out of a sense of compassion. In ESB, Luke isn’t saying stuff like “I need my friends,” or “I can’t live without them.” He says “They’re my friends. I’ve gotta help them.” He wants to help them because he has a good heart, not because of selfish possessiveness.