Why should they? It's ridiculous.
5 seconds sound clip from the Mister Ed movie soundboard.
You can hear this line at 00:17:04 in the DVD version of the movie.
Quote context
[...]
- The reason I came over here is I need your help.
- You see, I've got a problem with my wife. I can't convince her that the horse talks.
- I would say that your wife had the problem.
- Why should they? It's ridiculous.
- You're the only one I ever liked well enough to talk to, Wilbur.
[...]