Basically, I disagree with that interpretation. I'll raise you Volo's Guide, which went into Goblins in depth, including the cases and situations where individual goblins might strike out from their tribes and seek different or better lives. Their individual souls are only sometimes commanded and collected by their deity by force - they are not universally foresworn and forsaken, just heavily dominated. They are socially and culturally evil,
It's a good point.
I'll try to see if I can deal with the text and the meta issue separately. I am indeed guilty of relying on the 3rd edition text that made this clear - humanoid gods created servants, monster gods made slaves. 5e tries, unsuccessfully, to have it both ways: monsters are both inherently evil and culturally evil.
According to Volo's guide Goblins are as diverse as the humanoid races but they are evil because they live under oppressive hand of Maglubiyet. Goblins know that "when the Mighty One calls for it, even their souls are forfeit" Which, as I read it means goblins have the potential to be good
until Maglubiyet calls you to be part of the conquering host and, once he does, their free will is forfeit. So under this reading Goblins are in a position similar to the one Spike was in the last season of Buffy the Vampire Slayer (go and be good all you like but the First Evil owns your soul and can turn you to evil at any moment).
So, says the goblin, why try to be good? You'll just end up on the bottom of the caste system and Maglubiyet will eventually collar your soul anyway.
So you are right that it's possible for a goblin to be good as long as they haven't been called by Maglubiyet. A good goblin adventurer would need to pledge to another god before Malubiyet called them to a host.
Now, on the meta issue:
(if you, Niara, detect annoyance in these words
please know it's not directed at you. These words and my annoyance is directed at WotC)
Does this lead us to a less problematic reading of goblins? Do we escape the analogues to real social problem with the 3.5 to 5e change? Is better to think: evil because of culture and not evil because of tainted souls?
I don't think the change is better. We end up trading "racist" thinking for colonial thinking - creatures aren't evil because they are born evil they are evil because their culture is evil.
WotC has been in a period of self reflection and has apologized for the depiction of the Hadozee but I think they are just hoping that no one notices the gawd-awful, historically-terrible mistake of the Matizca campaign setting. The "colonialism can be fun" campaign setting. Now the setting never sold very well but it is referenced in BG2 - it's a setting where the human Amnian conquistadors were Lawful Neutral and the human Matizcans (read: South Americans) were Chaotic evil. In the logic of the campaign setting, the evil that the church of Helm does by forceably converting the natives is justified because Helm's sternness is preferable to the hellish damnation offered by the native gods.
I'd argue that this setting was infinitely more problematic than the Hadozee occupied Spelljammer setting and helps to illustrate the point that not only don't we make things better by saying "not evil because souls, evil because culture". Indeed
we actually make things worse. "People are evil because of their culture is evil" is an attitude that exists in the real world; people are evil because a goblin god enslaved souls at birth isn't.
*****
To answer your question - I'm not playing with a group now. When I did we treated negotiations with monsters they way BG3 presents negotiations with Raphael: necessary evils that put your soul in peril. Finding a way to force the paladin to go along with the group's plan was part of the fun. The cleric and the paladin in our party were a real life couple and she played a holy seductress . . . . but I digress. When we played in Ravenloft we never made deals for fear of a powers check.
