Well, to be fair, BFReds are (in BP canon) So far in advanced of everybody else that they should effectively not exist. Meson Technology is more (relatively) down to Earth, given the the GTVA appeared to have developed it entirely on their own, which to me means theres probably no reason the UEF cant do so as well, unless they run on some Phlebtonium not available in Sol.
As for beams, who's to say they haven't worked out some method of mimicking beam technology at this point? The problem is that refitting all of your vessels to use said technology is a whole different, and much more difficult and costly, matter entirely. And we already know that Earth's production capability does not allow them to just pop out a new beam-armed super ship, a la Inferno. Your research can be miles ahead of the competition, but if production cant keep up then it's all for naught.
That being said, building a warhead with a delivery system and a detonator is considerably less difficult then building a ship. I'm still probably pushing it here, but I don't feel that any of my points are too far out of the UEF's grasp. Practical applications of a space nuke aside, of course.
Edit: Sorry for the Bold. Mis-click.