The sign in the window said genuine antiques made to order so I decided to move on. Which best describes the speakers probable motivation to move on?

What the speaker was reading was a contradiction and a false advertisement. The reason this is a false statement/advertisement is because antiques are things that would have already been constructed some time ago (100 years ago). Thus, it is an impossibility that they can be newly constructed at the direction/discretion of anyone in the present; if so, the item could literally not be considered antique. Thus, the speaker most likely moved on because the speaker deciphered the sign’s message as a contradiction and a false advertisement.