My brother in Selune, if they didn't think it would work, they wouldn't be doing it.
They're not doing this out of the goodness of their hearts. I think you appreciate that perfectly well. They are literally, unarguably, doing it because they think it will make them money. They think it will cause people to renew subscriptions, or to sign up at Beyond and so on.
The reason they think that is FOMO or whatever term we want to call it (I actually think it's about 15 degrees off classic FOMO). You say it doesn't work on you, and I 100% believe you. FOMO is not universally effective. It never has been. It never will be. The videogame industry is a perfect demonstration of the power and lack of power of it. You have gamers who will pay $20 or even $40 (or in some cases more) to play a game for 3-7 days before it's officially released. You have other gamers who are 100% happy to not only wait for something to release, but to wait for it to go on sale.
So you are right - no-one can deny this is weak FOMO for you. You know your own mind. And it's probably weak or non-existent FOMO for a significant percentage of D&D players/DMs. But for some other unknown percentage, that Beyond surely at least hope is quite high, it is effective FOMO. And two weeks is a long, long time on the internet. Two weeks of being informed and able to discuss something or play something is, to a lot of people, especially those with more louche spending habits, significant. I mean, I'm not going to lie, whilst this wouldn't cause me to resub, that'd be stubborn-ness on my part, because I am pleased that my current Beyond sub goes to November, so if I do buy this digitally, I will be able to see it early.
As for "blame", well, I think it's a matter of sign rather than something itself to be particularly abhorred. It's not cool. It's not good. It's not positive. It's relatively minor but it's likely to be a sign of the future direction of Beyond, which is to say, the direction @darjr predicted earlier. It's not the first sign either - the first was probably stopping people buying specific contents of books and forcing them to buy entire books. The next will probably be either subscription price rise (not an excessive one - it's too early for that) or an extra tier on the subscription.
Getting something two weeks ahead of time is obviously a benefit, I just don't see how it is that big of a deal for a game like D&D. If I get an MMO two weeks earlier, that's two weeks I have to level up and be better than all the newbs who don't get it early. My advantage may be short lived, but it is still an advantage.
Is getting things a bit earlier a perk? Of course! Is it bad that companies do this or are they blocking all access? No. In my opinion of course. Obviously.