I mean back in the day, those kinds of titles involved film editing, not video editing. As in, physically filming title cards with a camera (and then maybe optically compositing them on top of other elements). It's easy to see how things could get slightly misaligned.

Looks like the misalignment is less than 1 degree. It's the kind of thing that stands out very noticeably in an image on a web page, when there are lots of perfectly horizontal edges to compare it against (e.g. the edge of the viewport). But I think it would be much harder to notice if projected onto a movie screen in a dark theater.