Because they didn't entirely fix said cheese nor was it the only problem. CT would be less obnoxious if they actually scaled it properly so we weren't fighting the equivalate of target dummies with a few auto attacks. There is no justifiable reason we're scaled to i130 in a bloody i50 raid. To be frank, the very poor scaling system is a problem at all levels because of how much we demolish content merely 4-6 months old. Look no further than Aglaia. New players won't even see the scale mechanic from Nald'Thal due to how poorly tuned the fight is on top of over leveled we are nowadays.
Secondly, albeit much less a problem overall is none of the other raids are required. Therefore, people deliberately not locked other 24 mans on alts in order to force the queue into select CT.
Instead of moving CT to MSQ, let's address the above problems. A simple solution would be to first gift new players a free set of Ironworks gear that way there's no concerns about them queuing in with i50 AF sets. From there, bump LotA to i70, Syrcus Tower i90 and WoD i110 with the sync being 20 ilvls above those requirements. For example, in this hypothetical, we'd be synced to i90 in LotA. That would actually make them more engaging to do despite level 50 being dreadfully working job wise. Going forward, all raids (and content, really) should be synced either 20 ilvls above the minimum or the relevant ilvl at the time of its release. I prefer the former as it helps mitigate how much stronger we are nowadays, what with job changes and all.
Finally, make all the 24 mans a mandatory unlock to access the roulette once you finish the expansion they release in. An example once again being once you complete the Stormblood quest, Alliance Raid locks until you unlock the Ivalice series. I don't typically like forcing things but it's the only way to completely eliminate cheesing raids.