Isnt wrong per se, as basically all postwar diesel submarines are based on the type XXI.
But I have the feeling they confused Venezuela's existing type 209 subs with the Kilos.
Type 209s are really a mixture of design features of type XXI and smaller postwar german subs, which are in turn based on designs made during wartime (type XXX and such).
Regarding supercavitating torpedoes, while it definitely is rocket science (rocket driven) a lot of countries are experimenting with them and the russians do not have a monopoly on the technology, they just have the first operational model.
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