they are strange to you because they aren’t English. For example, Genendel comes from German and Shprintza allegedly comes from Spanish (Esperanza). Why Jews chose them, I don’t know.
Also: numerous tannaim have non-biblical hebrew names, and numerous amoraim have non-biblical aramaic names. Rav Moshe writes about this at length, as I quoted in another thread. So you could ask the kashah on them, or you could assume (as does rav moshe) that it’s just not that big a deal.