Meaning: It not something your are interested in or willing to do/have.
Something you would prefer to avoid.

I am not feeling the scorn, personally, although there is probably some irony or indignation in it. This expression means that you don’t want to go along, or are not agreeing, or won’t do or use something.

Looking at your examples:

Les maths, très peu pour moi → I do not like or am not very good at maths

Le verlan, très peu pour moi → I do not understand or don’t like verlan

Brennan, Clapper, des gens comme ça, très peu pour moi → I do not like these people

It means “I really don’t like it“, “I’m not interested in it“, it’s rather formal. It can also mean (for math or verlan for example) that you don’t understand it, you’re not good at it. (Usually if you don’t like math it’s because you find it hard).

Sometimes, it carries the idea that you don’t respect it very much, or that you’re being sarcastically polite. WordReference has “Thanks but no thanks” as one of the translations.

You can see it that way : you’re at a dinner, the host serves a dish to all the guests, but you really don’t like it, so when it’s your turn you say “Très peu pour moi“, which means roughly “Give me very little, please”. You’re being offered something but you really don’t like it. You’ll still have some because you’re polite and it would be rude to refuse, but you’re asking for as little of it as possible.

très peu pour moi:

• j’ai déjà eu une mauvaise expérience …
• j’ai une mauvaise opinion, avis sur …
• je n’ai pas l’intention de …
• je préfère éviter …
• je n’aime pas …
• cela ne me convient pas …