Grammar pedants are the worst. It generally isn't very important if people understand what is being said. There are a few edge cases, but in general its pretty obvious.

In this case I (en-gb native) initially thought extravert was some tertiary alternative to extrovert and introvert; then assumed it was errant/en-us spelling.

I'd think of extro- and intro- as looking out and in respectively. Extra- and intra- would be externally additive and internally additive; like a connection outside a defined group and inside such a group respectively.

tl;dr this was an edge case for me.

Every linguistic anthropologist ever would like to have a word with you ;)

it's

my point exactly

Dunno, when you make egregious errors like that we can't help understanding not only what you meant but also some things you likely didn't mean.

It's been pointed out to me lately that "prescriptive grammar" is apparently classist/racist, which is strange considering I grew up dirt poor in Appalachia but still bothered to learn the difference in "who" and "whom". In languages like French it's a crucial understanding but English got lazy and for whatever reason, direct object pronouns are a tripping point for many students of a foreign language. Astounding.

You must be new to this planet.

It surely is. Caring about language (caring about anything, really) is an honest signal of status, whether you like it or not. Inevitably, some people will try to slave-moralize it away. If some social/ethnic/sex/... minority with inferiority complexes jumps on this bandwagon, suddenly you may find yourself caring about a thing whose ignorance some social scientists somewhere have found to be correlated with holy cows.

Proposed solution: stop caring about everything besides making all people feel good about themselves.