It is definitely advertising. Back when streaming services were new, the lack of advertising was a major selling point of streaming services vs cable but now they're stuffed full of ads and for some reason the ads are for content you've already paid for.
This is exactly what happened with cable. People were told to pay a subscription fee to avoid all the commercials of broadcast television. They got enough subscribers, and began the commercials. Years later and losing 1/3 of a show is the norm.
This is why all 30 min shows only have a 20-22 min runtime. We have all simply come full circle.
Hulu is going the same way with their commercials on my commercial free sub, and the commercials are always on content I'm paying extra for (HBO, Showtime, Starz).
I'm already setting up my Plex server. I'd rather not this be the case, but it's back to setting up scripts to grab from usenets and torrents.
Which, ironically, is precisely what Cable TV first promised in the 1970s -- an "ad-free" experience! They could offer this unique experience because you were paying the cable company for the costs of carrying the content. Then they realized they could double-dip by charging you for the content, and sell ads too.
It shouldn't be surprising to see the same behavior patterns repeated with this new crop of wireless cable companies. I'm sure the irony is lost on them though. We become the thing we try to escape. Stare long enough into the abyss...