I;ll say what I've said before, the marketing for these game was just odd, especially with how that was handled, on the one hand, I want to believe this them walking back after the criticism they got (though it annoys me seeing some journalists trying to act smug about it now after fuelling the fan rage or creating excuses etc). However, looking at the DLC, either they've crunched like Arceus to get that done fast as possible or they had this in the works for a while, which if that was the case, their was no need to lie because the surprise that Pokemon were coming back in slowly (which didn't need to spoil the expansions) was not worth what we had to go through for months, I had to leave the fandom for ages because the sheer warring and negativity was too much.
So I think this was an attempt to keep a surprise under wraps till a certain date and they didn't realize the backlash they got but were too stuborn to say anything that could ruin it. We've seen it before (like when Journalists leak news then the studio denies it).
It’s almost like things like this aren’t worth freaking out about because most games receive extensive post-launch updates these days and grow/change over time.
Were you not paying attention at all? Part of the reason the backlash and criticism was because they flat out said something like DLC expansions and Patches WEREN'T going to happen.