Use of singular "they" in English predates the US's existence by at least 400 years.
I think if people can learn new non-gendered terms like "libtard", or "snowflake", then they should be able to pick up this shiny new usage of "they" (and it only has half the syllables of the other two I mentioned).
https://www.oed.com/discover/a-brief-history-of-singular-they/