If Goodwin didn't accept a better deal from Portland because he was butthurt over the Blazers' ending with Dame, he'd lose clients. He's representing Brown's best interests here, not Dame's if he's negotiating a Brown deal with the Vulcans.
Yes, agents, GMs and players are people, but if you're constantly holding grudges and letting situations erupt, you're going to have a hard time being at the top. To think Goodwin wouldn't make the best deal for Brown with Portland because of Dame would mean Goodwin wasn't doing the best for his client, had lost sight of his goal and compromised his professionalism. He's not going to do that. People are overstating the longterm effects of Dame being unhappy.