While the old owners were far more generous than expected about it and never let anything expire, donations over there were always for a limited time, a year's subscription. I mean, whatever I donated way back when the site first opened, it doesn't help anybody with server costs today.
There was a change in management to someone who doesn't have the resources to serve up terabytes of data to users every month (those were the actual numbers, last year). "Free" accounts are worth about what they cost, at that point.
I don't know what "locked out" might mean, since you should still be a member and have access to the forum, unless they (like we've considered here) purged the accounts that nobody has used in a long while. But if you downloaded anything, that can't be the case.
The policy here is modeled on the original free-wheeling policy over at GAC, and is its original reason for coming about. However, as costs escalate, we may also find the need to limit the downloading of non-donors and expire donations. Hosting high-volume, high-bandwidth sites reliably isn't cheap, after all. So for now, you should be able to download what you want, but your dollar (if you contribute) isn't necessarily going to let you continue to suck down books in five years.
Lastly, since we're part of the same community, we're not really keen on people bashing the neighbors. While I get the frustration, you're basically calling their management liars because you didn't read the terms of the donation process and feel entitled to their bandwidth. I sympathize, but we're not going to let this devolve to "us against them," and would appreciate it (a subtle way of saying that any abusive messages and abusive members may mysteriously vanish into the night) our contributors holding that same standard.
Complaints about someplace else are best directed to the management of that place, just like you wouldn't stand on a table at McDonald's to tell your Burger King tale of woe.
Both sites are privately-run services on a shoestring budget, and we're very lucky that there's ANY access to many of these books at any price. And the surest way to kill it is for people to treat it like a service to which they have a "right."
You'll pardon the soapbox, but I've seen several communities fall apart due to the influx of people demanding to be treated (by their peers, essentially) as privileged customers.