Prior to the first year of my English Lit Master's degree (which I only almost completed), I did a little prep work by diving into the Norton Anthology. As a card-carrying member of the "My South African (British) English Is Superior To Yours" team, who'd always paid attention to spelling and grammar rules and developed micro-tics whenever I noted abuse, I was shocked, stunned and even flabbergasted by what I read there regarding the history of our Sacred Language.
That English derives its strength from its adaptability, from its acceptance and incorporation of other languages, accents and flavors, its tolerance of misspellings and a laissez-faire approach to even its strictest grammatical rules (just as long as things *sound* alright). And, of course, to its willingness to let us redefine our words in whatever way we feel is best at the time. Then I discovered Shakespeare's Sonnets - https://therightstuff.medium.com/how-shakespeares-four-hundred-year-old-sonnets-drove-me-to-madness-394ad7ea366d - and Helen Vendler's "The Art of Shakespeare's Sonnets", and bore witness to how wonderfully our words can be manipulated for poetic, aesthetic, symantic and symbolic purposes, and realized how little any of these "rules" have actually mattered at any point in time.
Alanis Morisette's "Ironic" used to bother me too, for years, until I realized two things. The first, which you've pointed out already, is the ironic used of the word "ironic" for a song without any trace of "actual" irony. The second, that for many years now the word "ironic" has enjoyed an additional meaning, that of "a state of affairs or an event that seems deliberately contrary to what one expects and is often amusing as a result", which it's full of perfect examples of!
So, in conclusion, I just want to share that all your language are belong to us. It doesn't matter if it's American, British, or broken, as long as we can communicate our ideas effectively it's totally okay if our writing gets the red pen sometimes :)