IMO, it means approaches from the point of view of architecture, that is, considering matters from the architectural perspective. But without any more context, it could mean anything else.
Information silo - Wikipedia, the free encyclopedia. From it, I would infer (wild, wild guess) that "siloed architecture" is the one which just concentrates on building aspects leaving out, for example, environmental issues or surrounding area (like building a castle next to a condominium area, for instance).