I wasn't weighing in on that part of conversation, just pointing out that the argument that the specializations is what allows you to use maneuvers was an inherently flawed one.
And on that note, the sidebar on page 135 (including the official errata) states:
Each style can be used as a skill specialization. Some of these styles can be a specialization for a combination of skills, or do not easily fit into a single skill and so are not listed here. The gamemaster makes judgment calls about what specializations may be applied to which skills.
immediately followed by a note that Chakram Fighting can be applied as a specialization to Exotic Ranged and Melee Weapon skill, which isn't one of the 6 listed skills. So, not an exhaustive list. Ergo, not proof that the list of specializations indicates anything.
Called Shot: Disarm can only be use with Unarmed Combat, but Bartitsu (a Clubs specialization) gives access to it, does that mean that can't be done? No
I would say a certain amount of common sense needs to be applied. I probably wouldn't personally allow martial arts specializations in the Astral Combat skill, but that doesn't mean that some maneuvers couldn't be applicable. For example, Disarm isn't a good choice in Astral Combat, because removing an opponent's weapon focus simply poofs its astral form, the Called Shot: Blast Out of Hands is much better. Most Martial Arts techniques just aren't going to make much sense in Astral Combat simply because the attacks aren't made the same way. There's no such thing as Superior Position above someone when gravity doesn't apply, you can't perform a Knockdown when everyone can fly.
Really, looking through some of the options, my gut reaction isn't necessarily "no, you can't do it" but more like "why would you bother?" 100% Astral combat doesn't use any of the physical skills, which gives good credence to the idea that you can't use Block or Parry defensive techniques (which also prevents the use of Counterstrike/Riposte). In those same instances, you aren't using the Close Combat skills, so a lot more techniques are eliminated. Really the list becomes quite short, so if there is a martial art maneuver that could potentially be used in Astral Combat, I don't see any reason why it shouldn't be allowed. But I can't think of any off-hand, so I wouldn't be surprised if there aren't really any applicable maneuvers.