How is it different than using “their”?

It shows you’re woke.

And/or using it ironically, as he does.

Unlike singular their, it's non-standard.

Some people feel like "their" is plural and therefore invented a singular gender-neutral pronoun.

"Their" is grammatically plural, even though what it refers to may be singular, plural, or neither (or, in some cases, may be unknown). "You" is also grammatically plural, even though what it refers to may be singular, plural, or neither. (Singular they seems to be from the 14th century, so it isn't really new.)

It is clear that it is singular.