For a lot of folks it's really simple: when you were a little kid, washday was a time of domestic tranquility and familiar routine. And kids like rhythmic sounds; reminds 'em of a human heartbeat. And there's warm water around, and clean smells, and that links up with the warm water in the bath tub and the smell of your sheets and blankets as you drift off to sleep.... in short, lots of warm fuzzy associations. To that add a fascination with all things mechanical (typical for boys, and lately more so for girls also), and there you have it. And then, add the current fashion for mid-20th-century artifacts, and the tendency of hobbyists in any field to have collections of whatever kind, and that's the rest of it right there.
So if anyone tells you you're crazy: no more so than a guy who's into antique automobiles and has a couple around and has spent time restoring them. Diversity is good, makes life interesting.