Christians didn't steal anything. Slavs became Christians and used wooden architecture to build churches like they used wood for building houses because it was most suitable in their local area. On the other hand Slavs along coastal area of Jadran used stone as a material for houses and churches because it is most suitable for that area. Only later in middle ages stone churches began to evolve in other parts and it was a gradual process.
I don't see much similarity. Ancient Greek;
PS. people i hope you all stop using your personal religious or non-religious views regarding architecture and i am critical towards all of you. Bottom line is we cant 100% know what kind of temples pagans had. Surely there are some remnants but we must consider the fact that architecture has gone trough evolution. The findings of early Slavic settlement of Prekmuje for example show us Slavs used simple zemljanka's and later by the 15th-18th century it evolved into this (so it is a huge evolutionary difference).