このことは、人間共通の宿命とさえいえる素因であって、なにも、ドイツ人に限ったことではない。

、、、。

This is a predisposing factor that could even be called a fate common to all humankind, and is by no means limited to Germans.

Literal

This thing [topic-は], humanity common [gen-の] fate [even-とさえ] can-say predisposition [copula-であって], nothing German-people [limited-に限った] thing [copula-ではない].

宿命 'fate / destiny' is a heavy noun implying something inescapable. とさえいえる 'can even be called' stacks と (quotative) + さえ (even) + 言える (can say). であって is the formal conjunctive of the copula, chaining clauses in academic prose. ~に限ったことではない 'is not limited to' is a set construction for broadening scope. A dense, essayistic sentence.