Well, based on the article, it says that they have a legal status which is recognized by the local community as a form of marriage. That implies a high (and anachronous) level of acceptance.
Where does the article say that? I see it says married, but people do have weddings and marry without the blessings of religious officials or the force of law behind them; this is especially true when people love and want to marry someone who they cannot marry legally or with the blessings of a religious institution.
Also, do the adventures in question say that? It's fairly easy for people writing articles to not do all the research they should, and the presentation in the adventures that actually gets into the hands of DMs and players is what matters because it's what people are going to see and use during play (assuming they don't modify the adventure).
But if so, then normalization is present, and it constitutes propaganda.
Do we agree on that?
Possibly.
If normalization is present does it constitute propaganda? If you mean propaganda in the common parlance of intending to elevate or denigrate, then no, most definitely not.
If you mean propaganda according to the definition of "information, especially of a biased or misleading nature, used to promote a political cause or point of view," then it depends on several factors:
1) Normalization could be an intended part of the campaign setting, in which case you then have to distinguish is it an artistic choice or is it politically motivated.
2) Normalization could be something that, even if originally unintended by the setting creator, makes sense in the context of the setting. Unlike the real world, I can't cite any major world religions in FR who decry homosexuality as wicked or sinful. In the absence of that influence, normalization is tremendously logical.
3) Does the viewer consider "homosexuals exist and are no more inherently good or bad than heterosexuals are" to be a political cause or political point of view? If so, then such a person would consider normalization propaganda instead of a basic fact that represents our shared human identity, and the potential that all people have within them to do good (or evil), regardless of their race, sex, sexuality, age, nation of origin, etc.