[mkleinstadt]

"Hertz" means "heart" in German, so the name is a pun on "heartbleed" and the unit for frequency

[minedwiz]

Almost, the word for "heart" is spelled "Herz".

[schoen]

I think it's still intended as a pun as Hertz (the physical unit and the name of Heinrich Hertz) and Herz are pronounced alike.

Wikipedia and Wiktionary also have some suggestion that the name Hertz is etymologically related to the word Herz, although they disagree about exactly how.

[Hublium]

In German, a <z> always makes a /ts/ sound and in modern orthography, "tz" is only used after (short) vowels.