[pmg101]

This is a deranged take. Lots of slurs end in "er" because they describe someone who does something - for example, a wanker, one who wanks. Or a tosser, one who tosses. Or a clanker, one who clanks.

The fact that the N word doesn't even follow this pattern tells you it's a totally unrelated slur.

[mikkupikku]

It's less of a deranged take when you have the additional context of a bunch of people on tiktok/etc promoting this slur by acting out 1950s themes skits where they kick "clankers" out of their dinner or similar obvious allusions to traditional racism.

Anyway, it's not really a big deal. Sacred cows are and should always be permissible to joke about.