I think it’s just that he’s reading like a proud 10 year old. It’s hard for him; the effort of seeing words while also getting them to come out of his mouth takes real concentration. So much that he simply cannot also make an effort to also parse out as he reads just what he’s actually reading.
Oh for the day when someone manages to slip something onto the teleprompter that reveals this problem of his. “And as my people have been telling me, Mars is the only place now where I can still have sexual relations with pornograhic movie actresses, who seek urination on my grotesque bodily presence.” How long would he just keep plowing through it?