I've done it in AE.
Make two text boxes, one aligned to the right and the other aligned to the left. Parent one to the other.
Sure you can do that in some cases. But notably not if you have different font sizes
for the Role and the Actor, because then the boxes will get out of alignment.
However it is still a "hack" rather than being properly implemented, as it is in Premiere.
If you have a request for an additional feature in After Effects, please submit a feature request.
You can animate and lay out text and graphics any way that you wish in After Effects. As a general philosophy, we tend to provide extreme flexibility and power rather than focusing on making a specific and narrow case a little easier. This tends to make After Effects very popular with professional motion graphics artists and compositors, who don't want to be constrained by narrowly designed and implemented features.
As Todd said, AE is not a "titling" program.
You can do exactly what you want, but you may have to dig deeper than an out of the box solution.
In this case you can just create your two layers of texts in precomps and align them the way you wish (make the precomp the Y scale of the entire title sequence) and then just animate in the main comp with Motion Blur
After Effects is not a typogrpahical tool although it's got amazing text capabilities. Similarly, I would not use AE's video layers to do editing, I'd use an NLE.
Regardless of the perceived need to have AE do everything, the typical workflow for film credits is to have someone design the typography in an illustration application, hand the file to AE for the special effects, timing, and compositing in AE.
Typography tools form outfits like Boris can do dual column text elements using a gutter but the results are not necessarily what a filmmaker would want in a feature.
Thanks for the link to request a feature.
However, WRG your comment "we tend to provide extreme flexibility and power rather than focusing on making a specific and narrow case a little easier."
I don't think that supporting left and right aligned tabs in the text box counts as " a specific and narrow case" :-)