"Invite" is a verb, and "invitation" is a noun. Journalists should know better.
You can say "I wish she was not so informal", but that's a perfectly reasonable use of the word.
Invite dates to 1649 and invitation dates to the 15th century. (m-w.com)
Surely it should be "I wish she were not so informal"?
"If she were a man."
As the writer is in informal in the judgement of the commenter, the commenter therefore should use "was".