I think one of the reasons that the new player stuff got a free pass was that we all expected the "big" update in December when the September update dropped. Had we all known that the new player stuff was ALL we were getting, then I think there would have been more wailing and gnashing of teeth.
But it didn't get a free pass. People were just as vocal about their disappointment that it focused solely on new players. Since most everyone on the forum was already beyond the starter bubble, they were incredibly demanding about having content for them right along side it.
I think a good question is WHY are Universal Cartographics not available on them? Legit question for spitballing here.
Did Frontier explain why? I didn't see the stream in full.
That aside, the WHY, as best I remember past FDev posts:
FDev has always taken the stance (whether players like it or not) that Carto Data can only be sold at a station to give exploration some amount of "risk." I put it in quotes because any seasoned explorer will tell you that's ridiculous and I tend to agree. Rather than make the void dangerous through phenomena, unknown aliens, secret human bases, etc. they decided making explorers return to civlization was a better course of action.
Now, part of the issue is that the galaxy is huge. I believe their intent was to keep players going to hotspots of player activity to encourage those spontaneous interations. Again, their reasoning was likely that Carto Data helps system factions, and I think they believed 1) explorers might be loyal to a system faction/PowerPlay and 2) other players would want to stop that influence by hunting explorers. Of course the Open v Solo play styles added it's own complications, the vastness of even just the bubble was another. Misguided as that all may be (there's no way to pilfer data, no recoverable data cores/black boxes, solo avoids any PVP), it is how they've kept the system.
Now, to be optimistic, there's a chance the end of year paid DLC may overhaul quite a lot of things. Perhaps they will make black boxes recoverable as has been suggested by the player base for years. Perhaps the Carto Data will become a different type of resource pulling NPCs to player-founded settlements in the black. Who knows. But I can almost certainly guarantee that they didn't design the FCs for the old game, but with the new game in mind. If that is even remotely close to their plans, then adding UC to an FC right now is a bigger problem. Imagine the outrage if they first gave it and then took it away.
Unfortunately, the only thing we can do without more info from FDev is wait and see.