From what I recall from my friends who were here for that patch cycle it was a bit of both. At the time Castrum and Prae were the only end game dungeons available and within weeks people had already found all the exploits the developers erroneously put into them. It wasn't out of malice, it wasn't because people wanted to rush out the sprouts, but by virtue of the fact that there was /nothing else/ until 2.1 dropped. That in itself speaks to the poor design of the dungeons twofold. First that they can be exploited to such an immense extent, which is probably why so many of the subsequent 2.1-2.55 dungeons have 'road blocks' every other room, and the fact that their own lack of initial end game forced players to use those dungeons in tandem with people who just wanted to clear the story. It was a /mess/ from all the accounts I've been hearing and SE fully deserved being made to issue an apology for that.
Likewise from my own perspective, I've never heard anyone claim these dungeons are well made even as far back as 2.4. Their pacing is atrocious and while I had friends who allowed me to watch the cutscenes for Castrum after begged for their help in defeating the queue I quickly started skipping them during my own initial runs once I realized how poorly integrated they were. I know many people who felt similarly as well and still do to this day. The story wasn't grand enough /or/ well crafted enough to warrant the pacing issues that I could otherwise have forgiven in a solo instance, and going back to it now only further cements the belief I held back then. For better or for worse, SE made two terrible dungeons and then got a lot of flack for the both of them for a variety of reasons. Regardless of which side of the divide you stand on /now/, I don't think anyone can really say the subsequent changes they made to how they integrate story into mandatory dungeons isn't an improvement. Because I sure as hell enjoy not having this same issue repeated in Aetherochemical and Ala Mhigo respectively.