Some elements of the OF are indeed ancient. Some of them have been made up on the spot. From my experience with people who have strong preference for the EF (I’d say I have weak preference myself), they do not usually claim that the OF has no historical basis, but that while the EF has developed more or less naturally over the course of, what, 1600 years, the OF somewhat negates the legitimacy of this natural development and replaces it with forced antiquarianism. As in, yes, even if the priest faced the people sometime in the 5th century, the Church has outgrown this custom and moved on. Same with communion in the hand, the kiss of peace, table altars etc.
Personally, sometimes, I have to agree. After all, it is curious, to say the least, to have the Pope write, in 1947, that
[…] it is neither wise nor laudable to reduce everything to antiquity by every possible device. Thus, to cite some instances, one would be straying from the straight path were he to wish the altar restored to its primitive tableform […]
and then, 30 years later, have table altars everywhere and, as an added bonus in some places, the high altars torn down. It can definitely give off the impression of “Hey, uh, so I know we have these ancient venerable customs that have been practised for a millenium and a half, but now we know
so much better, right? So here is how they did things in the 4th century. It’s
older, which automatically means it is
superior, doesn’t it?”