Perhaps it is because Malbolge is notable within the category of esolangs.

As an actual esolang enthusiast (and a past Wikipedia administrator two decades ago), I can say that Malbolge is only notable because it remained unsolved for the extended period only due to the lack of serious attempts. It doesn't even pass the meme criteria IMO.

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dickiedyce an hour ago | parent [-]

Although, didn’t it appear in a popular culture reference? I seem to remember an episode of “elementary“ that mentioned it.

	▲	lifthrasiir an hour ago \| parent [-]
		Oh, sure, the "In Popular Culture" section is a prerequisite for every Wikipedia article. ;-) In seriousness though, the Malbolge article (2003) significantly predates the TV series in question (2012--2019). I wouldn't be surprised that writers got the info from Wikipedia.