[mikkupikku]

Crypto[insult] is just a shorthand for saying "I don't actually have evidence to support my accusation."

[mock-possum]

No, it’s a term for a particular brand of racism -

Like complimenting someone for being ‘articulate,’ or ‘one of the good ones.’ Sounds innocent enough, until you understand the racist underpinnings.

[mikkupikku]

See above, where it is being used as an insult without any evidence to back it up. This is the most common usage, and usage defines the true meaning of the word.