americans and using anything except the metric system
How many football fields is that? 
I live in New York. 9/11 was like 35 9/11s for us.
But nearly 3000 people died on 9/11. For something to be 15 times worse it would imply that 45,000 people died.
Also this post is not a meme.
It’s proportional, as in how much of a spike it is on the countries average daily deaths.
Not that it matters. It became obvious that using “one 9/11” as a unit of measurement was no longer shocking a few months into 2020.
I love how people who keep trying to police what qualifies as a meme ultimately expose their own lack of understanding of the concept.
The definition of a meme could be anything at all, but that doesn't seem useful. So I concede that this could be a meme, but it isn't funny and doesn't belong here in my humble opinion.
I'd recommend trying to make some kind of joke with this rather than taking a screenshot of Twitter.
It's not anything at all, it's a pretty clear definition which is is an idea that spreads within a culture and often carries some symbolic meaning. You seem to be confusing memes with jokes.
but it isn't funny
"Unless I am personally laughing it is not a meme" 
Damn this inflation!
"Never Forget", at least not until the empire has cynically wrung the last bit of sympathetic credulity from the last oblivious grillman. 9/11s were never intended to appreciate in value; they are printed to be spent.
