I'm fairly sure no one ever said it was available either.
At one point, when I started my first free account little over a decade ago, they were allowed as were catchalls, not sure exactly when they were turned off however since I later moved my account to premium hosting.
I believe forwarders was removed a fair bit ago, although accounts created under an old plan (we're talking accounts that have been around for a few years) may have been able to keep them. I have seen during the transfers that there was a lot of different account configurations, from old plans mostly but also evidence that for whatever reason that not all servers were set the same way. I know one of the old servers was initially configured as a highrisk one when we did that for certain countries that was tighten down even further from the regular feature plan.
Now however we have made sure that all servers are allowing the same features and that all accounts, no matter the age, is under the same plan, the only exception being disk allowance that users can request to have increased when certain criteria is met.