That’s an awfully persnickety correction attempt for someone that replaced an opening capital letter and period with parentheses. That’s far more grammatically lax than using slang.

Americans and especially corporate culture America likes to do this all the time: The ask instead of request is an example. I just politely use the words I prefer when that happens.

Our new promotes for this year. etc.

I read from a linguistic source that it's a feature of English and the Brits do it as well.

Oxford dictionary lists cringe as adjective.

Cambridge dictionary lists cringe as adjective.

Merriam-Webster lists cringe as adjective.

Might need to update your understanding.

It’s shorthand for “makes you cringe” :shrug:

Verbing weirds language.

(English doesn’t work like that people use cringe as an adjective therefore it is one, it’s an extremely flexible language.)

It is both.