Yeah, you're right, you'd think Q would hint at the delta in some way :)
Because no one is stupid enough to take tweets like that at face value.
Probably more than one reason…
The simplest layer is probably pointing us to the more nuanced [2] definition of the term Patriot, and also the definition of [2] traitor. Often times the bracket markers are used merely to emphasize something within a single drop. Sometimes these seeming one-offs end up being something that the news confirms at a later date.
Beyond that, possibly pointing to a recent or upcoming [2] minute delta between DJT tweets.
I've seen numbers represented with dropping trailing zeroes before from Q, so it could be that
>[2] = [20]
[20] minutes later, DJT tweeted.
Just a few ideas.