There may be folks with some types of disabilities who benefit from using a drive thru, but there are also folks with other types of disabilities who can’t use a drive thru because they can’t drive and who are materially harmed by the lack of walkability drive-thrus cause.

In fact, considering that there’s nothing in the Americans with Disabilities Act that requires restaurants to have drive-thrus, and moreover that lawsuits regarding drive-thrus and people with disabilities tend to be almost universally about people who can’t use the drive-thru being forced to use it rather than the other way around, I’m very confident that my position isn’t ableist.

(And that’s considering your argument at face value, which is pretty charitable considering how often it’s made in bad faith.)