Huh?

So, I was channel surfing, and found myself landing on a cooking segment on "Rachel Ray."
She was making something called "Deviled Egg BLTs."
Being a fan of both eggs and bacon, I decided to watch.
Midway through the segment, she brought out a jar of mayonnaise, and mentioned that "vegans can use vegan mayonnaise."
I cannot help but wonder why a vegan would be making a sandwich of which the key ingredients are bacon and eggs.