The hol came from alcoholic. It's common enough for words at times to be reanalysed morphologically, and then one of the morphemes to be reused. Cf. -gate as a suffix, the n from the following word being fused to the preceding indefinite article, (e.g., an adder, an apron), the non-etymological d in admiral or h in author. It's a common enough process. You might as well ask where the al in alcohol came from. It's the definite article in Arabic, not a part of the word the Spanish borrowed. Yet, no grammar mavens rail against the al in alcohol and say, like the hoi in hoi polloi, that one shouldn't say the alcohol.

Ceci n'est pas un seing.